In Sanctum, the map is a grid, in which you place blocks to make mazes, towers on blocks to deal damage, and can also run around yourself to shoot at the aliens.

But, in classic TD style, you will not survive if you do all of one and none of the others. You must make the longest maze possible, because maze length is damage. You must place your towers in the best positions possible and upgrade them as needed, because a maze without turret coverage is no maze at all; just a delayed loss; and enemy health scales very quickly in higher rounds, so you must also juggle upgrading your towers and own weapons throughout this process.

Some simple important tips:

• Upgrading towers is not always better than placing more towers
  
• Placing more towers in not always better than upgrading towers
  
• Upgrading two towers is generally better than placing all resources into one
  
• Placement matters
  
• Vary your damage types for best effect

At any time, you can press the esc key to get a summary of the next ~5 rounds. Do this. The biggest fear are flying rounds, as there are very few tower types which are even able to fire at air units, and not planning ahead for them can leave you insufficiently defended. But knowing the next few rounds will give you a massive advantage when choosing what to place or upgrade next, as it will be most effective if it will contribute meaningfully to not just this wave, but the immediate ones after as well.

Also at any time, you can load your previous checkpoint. If you lose more than 20% core health in a wave, you really ought to reload your checkpoint. 'I can live without 20%' you say; yes, but it's not just 20% that you're missing. You also have a defense which has failed once already, which means that in two rounds when the same enemies that got through last time get through again, that'll be even more health lost. Save yourself from bad situations now, and reset time until you get your defense right. It's not necessary to obsess over keeping 100%; after all, once you get the achievement once for having done so, there is literally no bonus for it. But you need your next checkpoint to be in a position of strength. If you load a checkpoint into 1% hp, then not only do you have no margin of error any more for the rest of the map; you also know that your defenses are already not enough. Don't get into that situation.

Note that this does require some patience. For a 20 minute play session, you will not be playing a map from start to finish. You will be playing to get to the next checkpoint only. Though of course, the more time you have, the more of a map you can finish. But you can always save and quit, so don't feel too pressured to get it all in one sitting. Instead, be patient, and grind your way into a satisfying perfect victory.

So, you want to win. What do you need to do that? The Scatter Laser.

There are a lot of towers in the game, and a lot of strategies which can work. Generally, if you pick at random, you'll probably come up with something that can win. But, to simplify things, let me just tell you the tower you need if you want things to go smoothly.

The best tower in the game.

This is because it has decent damage when leveled up, excellent range, and decent fire rate as well. Need a swarm killer? Lotta Scatters. Need an air killer? Upgraded Scatters. Need a soaker killer? Lotta scatters followed by something heavier hitting nearer the core to finish them off. Scatter solves everything.

The scatter laser is your GOAT, 'ol reliable, the heart and soul of filling out your defenses. The random targeting means that a single scatter will not reliably kill a specific enemy in a swarm. So build more scatter. Problem solved. The random targeting also means your turret doesn't waste its dps against immune enemies.

But the real reason you pick scatter is as a fill turret. You place your core defenses. You place your secondary defenses. And now, you have roughly half your squares with no turrets on top, and a soaker round is next. What do you do? Blanket the map in level 1 scatters.

Scatters also level well. Against flying enemies, scatter turrets are THE BEST turret against the little flies enemy type. They jump around so fast that anti-air will miss, and have too little health to be worth a violator shot. But against a scatter laser, they get annihilated.

To effectively use scatter laser, level *some* up. The universal rule of sanctum is that you should be building/upgrading no less than two towers per wave, and most likely no more than 10. Scatter might be your 'fill with junk' option, but they aren't useless, and leaving all of them at level 1 will make them appear to be. Level up a couple of the scatters in the earlier part of your defense; that'll provide an opportunity for them to thin herds and kill fliers before they reach a dangerous part of your maze. And it also means that if/when they get overwhelmed and leak due to random mode, you will have your other defenses ready and waiting for it.

However, their low single-target reliability and low utility makes them not a reliable core damage choice, even at high levels. Scatter laser fills in a good defense; it is not itself the good defense.

Another caveat; scatter is essential on maps with air units. But if the map has NO air units, you can pick the gatling instead; it's a little cheaper, which is ideal for your fill turret. Just remember to switch it back when air units are on the map, as you don't need both.

(To know if there are air units on the map, try to equip the anti-air turret. If you can, there are. If the weapon is magically not in the list of equippable turrets, there are no airborne enemies and your life is much much easier.)

Whoops, did I say Scatter Laser is the best? I jest, I jest. If you truly want to win, the Anti-Air is your friend.

The best tower in the game.

There is one enemy type which, if you do not plan for it specifically, will ruin your day. Spore Pods. These flying bastards are air units, so already 90% of your defenses can't even target them. And when they do show up, they come with two things; ridiculous health pools, and ridiculous numbers. A scatter laser defense will get all 1000 spore pods to 20% hp, then they leak and kill you. A violator defense will kill 3 of them, then they will leak and kill you. The only way you will survive is to build anti-air turrets.

Anti-air turrets have one additional, secret advantage; if you can equip them, there are flying enemies, and thus you need them. If you cannot equip them, there will be no flying enemies on the map, and you can relax and enjoy your free victory.

They have similar range to a violator or mortar; so to get a feel for the range play a few games with either of these towers equipped. This helps because if you press 'tab' while hovering over a tower, you will see their orange targeting circle; *except* for anti-air, in what I assume is a glitch. So, when placing your anti-airs, hover over that box, equip a violator, DON'T PLACE IT, and press 'tab'; you'll get an idea of what the anti-air range will roughly equate to.

Flying targets also don't show the path they will take. However, generally they will have two spawns, and each spawn will take an 'S' and inverted 'S' route from the spawn direction towards the core. They will pass over all defense zones at least a little bit, but a central location in the front half of the map is generally where the two flying paths will meet. THIS IS WHERE your best anti-air coverage should go. Overlap is good for this point; You will place more than one anti-air, with the general categories of 'pre-damage' at the forward edges of the map, 'final defense' with coverage of the core, and 'main damage' in the junction point. Note that you definitely shouldn't be building more than four AA turrets, and that 'pre-damage' and 'final defense' are equally well suited to being scatter lasers instead. But place those core two AAs every time, and finesse their locations a little so that they always cover the junction of where the two air spawns meet. You'll get magical results for cheap by doing so, because there is where you take best advantage of the AOE.

But the most important takeaway is this; If you CAN equip the Anti-Air, DO.

But actually forget all that. Those towers aren't the best.. they can't be, because THIS TOWER is the BEST!

(It is at this point when I hope you realize I'm being a little tongue in cheek here. Please, equip all of these, you won't regret it)

The best tower in the game.

Forget those other two towers. They're for chumps. The real turret you need is the Accelerator. Why? Because it is a DPS god. Now there is a quirk; spin-up. So, against fast enemies and numerous enemies, it struggles a little. And against armored enemies, it'll get distracted and shoot the armor, a lot. Yet, if you place an accelerator next to any other turret, the accelerator will deal more damage, every time. All you need to do, is place it near a corner; in fact, place one near EVERY corner; and watch those aliens fall.

So, you have a tower that's worth placing on every corner, and you have a lot of corners because you're building a good maze. It's efficient just like that; best-in-class, even. And due to the excellent base damage, building a lot of them will be effective at thinning medium-health groups, too. Just keep your accelerators leveling up slowly over time, and they'll reward you by doing a *very* good job.

But they can be made EVEN BETTER.

With the player weapon slow cannon, or the slow field floor item, that spin up happens more consistently and max speed happens for longer. With both? DAYUM that's a lot of damage. What's that you say? Are we discovering a secret, OP wombo-combo which can trivialize all boss enemies? Yes... yes we are.

With these, the accelerator is INSANE. But even without, they're still a core pick.

Just don't place them in a bad location, or they'll do nothing at all.

But, secretly, there is another. One even more secret and powerful. The one tower to replace the players themselves, and remove the truly irritating enemy types.

The best tower in the game.

You want to win, but bobble heads keep getting past your accelerators. And those darn front-armored units just float past it all, shielding the big walkers and wasting your perfect death zone. What can you do?

Place drones, the perfect anti-annoying-unit tower.

A drone will latch on to a unit, and deal the full damage over the full duration. It's well positioned to take out the shielded floaters, and weaken or kill your bobbles; but it will deal damage to ANYTHING. Big walkers? Drone will whittle them down. Runners? Drone will kill whichever one it latches onto. Even normal walkers; the drone won't kill many, but it *will* remove the ones it *does* hit. And it's perfect for adding DoT to your anti-soaker defenses, too.

Drones are nice because you don't need many of them to do a good job. Place them so that, if there were only one big walker, they would have a drone on them 100% of the time. Level them up slightly ahead of most of your accelerators. And, what's that? They're dealing how much damage?! Drones are goat, they just need time and space to show it.

Drones are also the core of why you as player can become redundant. Because they delete the units which would otherwise require direct intervention. This is the ultimate reliability and convenience turret, and as such I can not recommend them higher. Which, obviously, makes them the best (TM) turret in the game.

Guide over; equip the above turrets, plus the tesla gun in your player equipment.

Reload your checkpoints.

And you'll probably beat any map.

But, for thoroughness sake, I shall provide more guide below, if you're curious to get even *more* in depth.

Beady-eyed readers of this guide might also realize that AoE is hitherto absent from the 'best towers' list. And having a land-based AoE solution is absolutely essential to succeeding. But there are two issues with recommending a ground-based AoE tower in sanctum. The first is the options; there are no good ground-AoE turrets. The second is the alternatives; many player weapons provide excellent AoE.

Similarly, you have two tower slots left (3 if no air enemies). That's enough to have fun with, but only if you don't just fill it with mortar and violator by default. But we'll address the AoE towers first.

Your option is mortar. It has a good range, but terrible travel time, so against a fast enough enemy it does nothing. The mortar shells have a terrible habit of hitting the edge of boxes or targeting outliers, doing effectively nothing. And their raw damage is SO low, that a super expensive, high level mortar will be outdamaged by a base level accelerator against 90% of the enemy types you'll encounter.

There are, thankfully, some ways around having to build this embarrassment.

Killing Floor is my current favorite; it deals damage to everything on the square when it activates, so the AoE range is garbage; but the upside is it never misses. place a few early map killing floors, and might as well place one at the last square before the core... and you do a lot against the smallest swarmers. But it also deals non-trivial damage against larger units, too. At least on a per-shot basis, though it has a reliable downside of hitting an average of half of the units that run past it due to the slow fire rate and tiny range. So it's an incredibly mediocre tower, but we're competing with the mortar here, which is equally mediocre. And it sits on the floor, which is cool!

Scatter lasers are another. You build one scatter laser, it deals mortar damage but to only one enemy per shot. Mediocre. You build 20 scatter lasers, suddenly you are *effectively* dealing constant AoE damage. Does it struggle against super-concentrated groups? Yes, but it also kills fast enough to be okay at it. Best of all, you ALREADY HAVE scatter lasers, so that turret slot is now kept free. More flexibility, ahoy! If on a non-flying map and going gatling instead of scatter, I assume it'll work just as well. Can't promise, but the math works out.

The penetrator also technically exists. By design, it is intended to hit multiple targets, as well. But, frankly, don't. Just don't.

Ultimately, the real solution here is obvious; player damage. You should have equipped the tesla cannon. It is the single objectively best choice. And as such, it has a primary fire that deals AoE damage. And a secondary fire which deals sniper-damage but chains 3x. Either way, you're hitting multiple targets, and that means solving your AoE problems. I guarantee, of the many times I have had to reload a checkpoint, large groups of small enemies has been the rarest, simply because of being carried by tesla cannon, accelerators, scatters, and drones. Which, frankly, translates to being carried by the tesla cannon.

Buuut, as maligned as it is... the mortar is still okay, if you must. It really works just fine, just don't feel like you *have* to take it.

So, you don't want a mortar (or maybe you do, they aren't *terrible*).

What else can you take?

I currently like Killing Floors. They are a not-mortar aoe-type solution, which mixes things up nicely. And they go on the maze itself, which gives more room for extra scatter lasers on the boxes themselves. Don't underestimate the value of a turret that doesn't require a block to sit on, it's actually really nice.

Lightning is less good. It deals chain damage, which seems nice, but has short range, low fire rate, and only chains up to twice, at a ridiculously high level, and the chains do progressively less damage. You can get this tower if you want to, and you can succeed with it; but you absolutely can survive without them, too. Compared to killing floors, they hit 3 targets rather than all targets under their area of effect, while having similar damage per hit. And they require a block which could've held an accelerator, drone, or scatter laser. Thus, they are made redundant. But cool looking. Never underestimate cool looking.

Violators, same. They fit the niche of providing global-esque damage, which seems nice. They genuinely make dealing with the front-shielded units simpler, as if you place a few violators on opposite corners of the map they'll actually have a chance of hitting weak spots and not just armor. But they also are relatively low value in terms of actual damage output. They're fun, relatively harmless, but similarly, relatively unhelpful. But hell, sometimes you just want to place a ton of violators on the edges of the map, I have. Won those maps, too. So, really, what's the harm? These are also, technically, the objective best turret against those flying bat creatures. So if you aren't running the tesla player gun (you monster), and ALSO aren't taking the sniper rifle (I'm upgrading you to psychotic), you might consider using these to help shore up your defenses on that particular front.

Kairos? Well, I frankly don't know. It targets air units, so you should already have enough anti-air to not need a kairos. Thus, it seems wasteful to take? But who am I to judge, it's a free slot, do what you want.

Penetrators? I'm pretty sure this tower was put in the game as a literal joke.

Amp field? Well, it boosts damage, sure. But only *directly*. It doesn't buy you more time. It doesn't synergize with low-fire-rate towers. And it doesn't have a disgusting wombo-combo with accelerators. So unless you want to pick the worse option on purpose... don't.

Because the true cream of the crop is the slow field. In fact, on further reflection... it might just be...
THE BEST TOWER IN THE GAME?!?!?!

For real this time.

The slow field is a tower booster. Don't get confused, slow seems lame but a damage multiplier is actually what you get here.

A level 4 slow field offers a 50% slow according to the in-game stat. A 50% slow doubles the amount of time your towers can shoot at whatever is in that square. That means your accelerator gets max spin time. That means your drone can fire two or three times into a dense pack. That means you win.

Slow field is your ultimate last level of upgrade.

Let me break it down.

In the early waves, you are building your maze and placing your minimal turrets. Each wave means you can place more, which improves your overall defenses, and you might get a level 2 on one or two towers, perhaps.

Mid waves, your maze is done. Your towers are placed. Mid waves, you need to figure out which tower you're upgrading, or if you really do need to place a few extra or upgrade the ones you have. Generally, the answer is a bit of both. Midgame ends when you have every tower placed, and all the towers you're going to level up at 3 or 4.

But late waves; you've upgraded your core towers. You've filled out the map with fluff towers. Level 5 is affordable, or you can juust barely afford a single level 6 (but remember, I warned you against putting 100% of your money into a single tower); so you aren't sure if you should get your secondary killzones to 5 or work some of your less-garbage fluff up to 4.

Without slow fields, this is where your defense will falter. Your highest damage killbox doesn't deal quite enough damage to justify level 6. Or maybe it's at 6 already but it just can't do enough. You spread out to level up your secondary killboxes, boost the pre-damage zone, boost the post-damage zone, but every time, your upgrade cash is going to further sub-optimal towers, and your enemies are getting closer and closer to taking the core. And the worst thing is, there is nothing you can do to stop it. You can only level everything up as far as you can take it, and hope that it's enough because it's getting prettttty close over there. And then you win, because even on the highest difficulty, Sanctum isn't cruel (Sanctum 2 on the other hand, is a different matter).

But what if you had another avenue for upgrade? What if you could significantly boost the effectiveness of every accelerator, by placing a cheap tower that *doesn't even take square space* so you don't have to sell anything you already have?

Slow fields are the solution to all your late game problems. It makes your endgame killbox absolutely inescapable. It boosts the effectiveness of your existing towers, so all the money you already spent is gaining increased efficiency and effectiveness. And it turns the accelerator, an already fantastic tower, into a disgustingly powerful, almighty minigun firing violator shots (seriously, did you not know? yes, the damage per shot is that high, nay, *higher*).

So take the free wins, and bring a slowfield.

You might recall we left AoE with a big 'solve it on the player side' open end. So, lets solve it!

The player needs the tesla gun, freeze cannon, and whatever they want in the third slot.

The freeze gun is simple and beautiful. When it's off cooldown, you primary fire it at the front of the enemy group. The cooler sticks, you switch to the tesla, deal some damage, then switch back and do it all again. The cool ball magnetizes to a target, so aiming isn't too hard, and the range is fantastic. And best of all, you never really need to put levels into it. Get it to 2 or 3 just to not waste money, and you have a ~30% slow over the entire map against whatever the greatest threat is. Against a single big walker, that means 30% more map, longer accelerator durations at crucial corners, and general massive damage for everything else. Against a swarm, the slow-ball will clump them together as unslowed units run into the slow aura and get slowed themselves. Wipe them up with the aoe from the tesla primary fire, and listen to the cackle.mp3 of your character. Relax. Then alt fire the big freeze at the biggest enemy right when they walk under your highest level accelerator for *massive damage*.

And yes, the slow stacks with slow floors. Yes, it is magnificent.

The tesla, similar. It provides a solution to every damage contribution the player is required to put up. It offers an aoe solution, an smg solution, and a sniper solution all-in-one. And best of all, if you time your shots just right, you never even need to reload!

As far as the player is concerned, there are three types of enemies. Standard enemies, enemies with weird weak spots, and enemies which group up. The tesla solves all of them. Don't believe me? I'll break it down.

• Swarmers:
  Fire freeze cannon primary, on cooldown, to make clusters. Hold down tesla primary fire to kill clusters. But also upgrade your aoe tower of choice, you'll need a little help with these.
  
  
• Small Walkers:
  The same thing? What?
  
  
• Soakers:
  Primary fire cold and tesla until it falls. Simple, same as above. And remember to place your scatter lasers; they'll help charge up the soaker bubbles with their combined fire rate, making them easy kills with your tesla alt fire or just a back line accelerator.
  
  
• Big Walkers:
  Focus on using your slow cannon at 100%, and just throw some tesla alt fires (hereafter, lightning bolts) when you have time between slows. The tesla primary damage is nonetheless better than nothing; don't underestimate it, just don't rely on it here. When you're hot swapping the cold primary, use the tesla secondary; their cooldowns are almost exactly in sync, and you get the best of both worlds. If you do the cryo secondary to lock a big walker in place (e.g. near your accelerator kill farm) use your tesla primary fire for a while; it deals comparable dps while being far more sustainable while you're waiting for the freeze to come back online. Tower wise, your accelerators and slowfields will be the biggest damage dealers here; make sure you have more than one accelerator leveled decently, and if you have the cash to spare, place at least one slow square under your strongest one. Do this, and you can relax.
  
  
• The tall fat tanks with shields that break and reform:
  Here on, tesla alt fire will answer every question - the higher per-shot damage pops the shield faster, and the lightning bolt will likely chain to the other targets around their feet. Be careful not to accidentally use the freeze alt fire when hot swapping, I have wasted no count of long cooldown freezes by such a misclick. Towers for these guys aren't so specific; just keep slowing them and lightning bolting them to keep the shield broken, otherwise your towers won't be dealing nearly enough damage.
  
  
• Runners:
  These guys have so little health, they die to either primary or secondary. But they tend to group up too far for the fesla primary aoe, but juust the right distance for the secondary lightning to jump. Wait around a corner, where they'll slow down and group up a little, then blast em with the chain shocks. Towers are anything, they die fairly easily; just make sure your maze doesn't have too long of a straightaway, they get *very* fast.
  
  
• Short fast ones which go into turtle mode:
  Two tesla lightning bolts will generally put them into hibernation. They also still take damage (albeit reduced) while *in* hibernation, so pop them under an accelerator for a quick and easy cleanup. These guys will absolutely run through your defenses if ignored, though, so do be sure to hit them at least once with the big zeus.
  
  
• Shielded on the front floater bois and bobbleheads:
  lightning bolt their weakpoints. They're both a pain to hit, and technically you'd do better damage against them with an equal level sniper than with the tesla since they don't chain shots well, but the point is you don't *need* the sniper, you simply *can* get one if you really want it. These waves are tricky as hell, but I promise you, you can do it. If one of these waves is coming up next, level up your drones; if they're high enough level and placed well, these waves go from being the hardest to the easiest, and you can just sit back and watch.
  
  
• Spore pods (flying meatballs):
  Lightning bolts deal good damage and chain to other targets. It works pretty well; possibly even better than the REX. Just alt-fire to victory; but you will need anti-air turrets, remember that.
  
  
• Those jumpy mosquito flying enemies:
  Lightning bolts, again. They're hard to hit, but you have the solution. But maybe just level up your scatter lasers again and shoot at something else, these guys are a pain to hit.
  
  
• The Flying Bats:
  Lightning Bolt! A crit'll usually one-shot each one, might jump to kill another, and they tend to come in low enough numbers that you the player can practically kill them all, alone. Really good fit, and you don't even need the violators to help you here. But if you have violators, placing a few will erase the bats, and you can ignore them entirely!

Oh, and you get a third weapon slot. Do what you want with it, you're free! You won't use it much, but having a backup sniper or rex can help with niche situations where you need just that little bit of extra DPS, and you can't really go wrong with either.

So, you have your towers

• Scatter Laser
  
• Accelerator
  
• Drone
  
• Anti-Air
  
• Slow Field
  
• Killing Floor (/Violator /Mortar)

What do you do with them?

First, let's get some terminology.

For mazemaking, I will focus on three terms; switchbacks, roundabouts, and zigzags.

For turrets, there are two terms, coverage and bites.

Hopefully this gave enough ideas for your defenses to shine beautifully.

I had a lot of fun writing this monster, and while it may not be perfect, I can also promise it works... at least for most maps.

But, as mentioned in the foreword; this is still only *one* path to victory. The main thing to do is have fun, and once you've used this strategy to win, fun might well involve changing things up a little.

I hope you enjoyed the read, and expect you to now win some games!

Good luck!