If into this mode you go, only pain will you find.
Don't try this game mode until later. I say it'd be best to wait until you've completely finished the game before trying Rebel Yell, which is a very difficult survival-style gameplay. More on this later.

Petty Thug: Absolutely nothing special about these snowflakes. Just put 'em down.

Big Guy: He is notably bigger than the rabble of petty thugs. If you find out what he has been eating, my Rebels would very much like to know. He wields a shotgun and at close range will devastate your Rebels in spite of their cover.
Arresting this chunky boy will be a real trick. The shield icon above his head means he will take more than one stun attack to take down. You need to hit Biggle von Chadwitz here with two baton strikes or two tasers in a single turn. You can absolutely mix and match, too.
The first strike will yield nothing except the sound of a baseball bat breaking on his fat skull. The second strike (the one that actually stuns him) gives 35 XP to the Rebel who executed the attack. The Rebel making the arrest will get 100 XP for this feat.
Don't try the trick where you get a whole gaggle of Rebels taking turns clubbing the crook for free XP. You can't klonk the Big Guys multiple times, and he'll start unloading his shotgun on Johnny Reb. Don't try using your 'Freeze' skill on him, either. It's practically a guaranteed fail.
Thankfully they are just as vulnerable to supersonic lead projectiles as any lesser street scum. One shot can still equal one kill.

Orcs: These wannabe lumberjack hipsters run about the battlefield with nothing but hatchets. They have no ranged attacks, but can instantly kill any Rebel they get within one space of. Their attacks ignore all armor and cries of protest. They can be easily dispatched with bullets, knives, batons or tasers just like the petty thugs. Take them down before they get too close.

Don't die, that'd be dumb.
You are stuck obeying the tutorial's orders until a certain point. After that, free the remaining hostage(s) in the lobby for some experience points.
Move towards the vault, but do not peek around the edge of the door. If you can see in, the bad guys can shoot out at you. Get all three of your guys ready to storm the vault, then wait an extra turn to get Allardice a third AP with his Patience perk. The hostages inside should be safe until you're ready to charge. Don't bother trying to arrest the criminals. Once both are dead or dying the mission is over and you win.
Like in This is the Police 2, I only recommend shooting for the chest except in very special cases. Any other body part has lower chance-to-hit. A criminal with a hand injury will raise the alarm and run around until you arrest him or he bleeds to death. A criminal with an injured leg will continue to shoot at you until you kill him or he bleeds out. The head or the chest will take the criminal out of play.

Now remember that the reason you went all outlaw was to help the people of Townsville. Reputation with them will be important for your long-term survival and prosperity. Be generous in the early game. Giving the people a few hundred dollars now and completing a few side missions for them will cause the store to drastically lower its prices later on, saving you thousands as you buy up the better weapons.
The store will pop up any time you finish a mission. You should never hit the "sell all" button, as the beggars of the town will demand you fork over your hard-earned payout. Instead, sell each item individually at the store. The threshold that triggers the begging is around $400, I think, so try to make your income in smaller increments, as the amount of money you give them doesn't matter, it only matters what percentage you agree to donate.
The store is the only place you can reliably obtain equipment. Your first few visits will probably be mostly limited to restocking ammo and any buying any pistols that are available.
Side note: your Rebels resting at base camp don't need any equipment. You really will only need weapons, ammo and equipment for the mission you're embarking on and maybe start stocking up for the next one.

Revolver: The classic. Cheapest and worst weapon in the game. Ammo refills come in packs of six. The range is limited, the accuracy is sub-standard and it isn't useful during stealth missions, either. They're cheap. Start selling them once you have pistols for your Rebels.

Pistol: The sidearm of choice. This weapon is more expensive but completely worth the price. Ammo comes in nine round magazines. They are more accurate than revolvers and can be paired with silencers to shoot seven or so rounds without raising the alarm. The silencer will repair itself at the end of the mission if you didn't break it through overuse.

Shotgun: Handheld siege weapon. The shotgun fires shotgun shells, in case you were wondering. They're sold individually and can be expensive if used extensively. The shotgun is great for hitting enemies behind cover and has terrific accuracy within its short effectiveness range. There are no attachments. It may be better for telling criminals to 'stick-'em-up,' but the true calling of the shotgun is to put bad guys down.

Rifle: Very important weapon to have. The rifle has the longest effective range, allowing Rebels to kill bad guys before they get close enough to pose a threat. The rifle ammo is sold individually, and like the shotgun, becomes expensive to use regularly. Keeping Rebels alive and their armor intact is worth the investment, though. You can attach a scope to the rifle, further enhancing the accuracy, especially at long range. Your Rebels with accuracy perks probably won't need scopes, though, given the rifle's extremely high base accuracy.

Medkits: I'll finish this section later. Bring a handful of big medkits along on every mission. You do not want to lose Rebels you don't have to. Small medkits aren't worth it since they may not heal severe injuries. Save your inventory space for better equipment.

Tasers: Tasers give your Rebels more flexible options for quiet takedowns. Tasers can also prove more accurate than pistols at specific ranges when the filthy rodents are hiding behind cover. A criminal hit with the taser is stunned for four turns, making an easy target or allowing for an easy arrest. They recharge over time instead of expending batteries this time.

Batons: Just like in the last game, batons stun enemies directly adjacent to you. They won't stay that way for long (two turns?), so arrest them quickly, or keep ruthlessly beating the criminal scum.

Knives: You don't have to bother arresting everyone, sometimes that will slow you down too much. Stab them with your handy knife to remove criminals from play in a single turn. Unfortunately, the knife takes up an inventory space in this game, so it isn't as overpowered as last game.

Flashbang grenades: Expensive, but oh so useful, especially in the late game. The area of effect can stun multiple criminals from a decent distance. Buy them up when they appear in the store.

Helmet and body armor: Buy as many of these as you can. Helmets and body armor will protect your Rebels from head and body injuries, respectively. The body armor can absorb two hits to the torso and extremities. The helmet only one. After taking the prescribed number of hits, the armor is destroyed and cannot be reused. These will be extremely important for saving Rebels' lives during the late-game firefights.

Lockpicks will come in handy for a number of earlier missions that will allow you to access shortcuts, find more loot and take criminals by surprise. They open the few locked doors and windows that aren't already open or controlled by key codes.

Don't buy anything at the store except batons before this mission. You really should only need the 5 revolvers you start the game with, those batons and a couple first aid kits. Once you build up your reputation a little everything at the store will be much cheaper.
Accept the side mission. It'll actually make the level easier and boost your reputation. Sending some Rebels to the side-mission entrance lets you take out the whole security force faster. You are on a short timer for the first half of the mission.
Sneakily stealthily bludgeon or stick up and arrest all the security guards around and inside the station. If any of them die you will lose reputation with the locals. Reputation is more valuable than Rebels or money at this point in the game. The last two guards before the switch will be the hardest, so have several officers stacked outside the door and lurking outside the windows to take them down with no shooting. Then throw the switch and get ready for the train. Make sure everyone is behind cover, because the bad guys come out swinging. Save your progress here, because the outcome of firefights are very dependent on RNG.
Your Rebels are going to suck at gunfighting this early on. Stick to cover and exercise extreme caution as you battle your way through the end of the level. The boss will be patiently waiting. Don't look inside the shed or he may start shooting. You can't take him down as you normally would with batons, so use a taser or flashbang before moving in on him.

Member when photo studios were a thing?
I say you should accept this optional mission and either do it for free or for cheap. The mission is worth more for the reputation than the money anyway. You can get some good loot here to help buy equipment for your next big mission and having friendly townsfolk will save you a lot more dough in the long run.
You'll have some tired Rebels afterwards, so ultimately the choice to do this or not (and how many Rebels to take) is up to your discretion. There isn't much XP to be gained here.
Do not allow the alarm to be raised at any cost. Your Rebels will not fare well in the firefight that follows an alarm. This early in the game they are lacking the experience and equipment necessary to outmatch the bad guys that will show up.
Bring pistols with silencers, melee weapons and tasers. Take it slow, make it quiet and carefully check every room.

This is a massive map with a ♥♥♥♥♥♥♥ of enemies. (150 or more) Make no mistake, this is a hard level, but it is possible to beat. Save very often.
Bring all your equipment, from sidearms and silencers to rifles and shotguns, armor, tasers, flashbangs and medkits. A couple lockpicks could also be helpful. Try to take down as many bad guys as you can quietly, but don't shy from a shootout. Raising the alarm in one area won't always alert enemies in nearby areas. However, raising the alarm near the hostages may result in their deaths and raising the alarm near the pier will rob you of a convenient evac area.
You have two choices:
Option one is to speed run to the main house, grab the papers for objective 1 (requires exploring some outbuildings to find the code to the door) then follow the clues to objective 2.
Option two is to accept every optional objective you can. If you just accept that this mission could take over 100 turns and a couple hours of playing, you will get massive amounts of XP for every Rebel on the mission, gain huge amounts of reputation points and take home thousands of dollars in loot. As the sun comes up more guards will arrive and reinforce the existing patrols, so be sure you've thinned out the local forces before 'Old Spice' has a conniption fit. I always pick option two to set up my Rebels for success later in the game. You'll be walking right by many of the optional objectives during the main mission anyway. The only side mission I can't fully recommend is the hostage rescue. The hostage in the sawmill will die if you get spotted nearby, which will make you very unpopular with the locals.
Also be sure to get away from the front gate soon after starting. Bo and Luke Duke will come charging in and start taking random shots at the guards. They will shoot at your Rebels if they get too close. These guys won't raise the alarm and can help thin out the criminals along the main drive, so I say keep out of sight and help cover them until they get themselves killed.
Here's some pictures, I hope they help. [Remember to insert pictures]
You should also check out О5-CblPO4EK_2020's guide for more tips: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1886458870
At the end of this mission, keep all the money to yourself. The villagers will be unhappy, but they should still love you if you've been doing the side missions.

You walk into a gunfight. Stealth is not an option this time. Your equipment loadout needs to reflect this. Be prepared for several waves of enemies. Use discretion: you don't have to be in the middle of this fight.
Also, make sure you save the boy hiding inside and arrest at least one of Zuev's guys. You may have to kill some Sharpwood grunts to keep them from killing all the thugs.

Start with stealth, but do not count on staying hidden forever. Speed is more important than staying hidden here. You can win a gunfight here, but only if you're smart about it.
Send your best Rebel up the runway with a rifle. Everyone else will need to be taking down baddies by the office and the hangar. That way you can get XP for both stopping the plane and saving your Rebel.
There are plenty of baddies, including big shotgun wielding guys. Refer back to the section on enemy classes.

Bring all your tasers and flashbangs. Pack plenty of medkits, too, because you are running headlong into a firefight.
The mission begins as a shootout between Sharpwood's Finest and Zuev's thugs kicks off. Both sides will shoot at you, too. Like the other path, there is no stealth. The mission requires you to keep one of the gangsters alive long enough to arrest him. You can let them take a turn or two thinning each other's numbers, but don't wait too long. The crooked policemen will likely kill all the criminals while also taking shots at your Rebels.
Once you arrest one of the criminals, you learn about the boss' location elsewhere on the map. Proceed with caution, as two warring factions now know you're here and will send reinforcements.
You will have time to get the side mission objective and what little loot is in the area once you take down all the bad guys.

Alright, you should have enough tasers, rifles and silenced pistols to make this mission a breeze. As always, accept the side mission. Assign two Rebels to it in order to go after the bombs more quickly. They are at the left corner and right corner of the building toward the top of the map. Just get in front of them and use one AP to disarm them. Once both are disarmed you can finish the level without a time limit.
I reccomend keeping things quiet, especially since you're trying to rescue a captive Rebel who has two shotguns and a pistol pointed at his head. Read the section about different enemy types before jumping into this mission, as you will encounter big shotgunners.

This mine is filled with murderous orcs armed with battleaxes. You are going to blow it up, which is like a bomb defusal mission but in reverse and you get to set the timeline. Due to the explosive nature of the mine, all your takedowns will need to be done with melee weapons or tasers. Be patient and watch the enemy carefully. Remember to stay close to each other in order for the buddy saves to work.
You can equip more than one taser to each Rebel, if you have enough. This will be handy since 'Old Spice' only lets you bring three Rebels along.
Make sure you arrest all the workers- they're the guys who aren't carrying battleaxes. They're innocent and you don't want to lose the reputation points by blowing them up with the mine. They can still raise the alarm, though, so treat them as hostile until you can arrest them.
Accept the side mission to grab Gandalf's body. His body is right next to the first bomb location.
If the alarm is raised you're totally screwed. These orcs will blitz your Rebels and kill them with a single hit. Read the section on enemy types for more info. If you want to go head-to-head without any firearms, go ahead and try. I'll wait for you to load your last save and come back.
The only loot worth mentioning is in the top corner, hidden behind a vehicle.

This is a straight up siege. You're the defender, a polite word meaning outnumbered, surrounded and not deciding where the battle takes place. Criminals will swarm in from every angle and will enjoy plenty of reinforcements.
There is no loot and no need for lockpicks.
You need all the guns and lots of ammo. No silencers. Tasers can actually be more effective on enemies behind cover than pistols sometimes, so may as well pack them. No batons. Knives may prove handy if the enemy gets in too close. Bring ample medkits if you value your Rebels and the equipment they carry. This level has no evac point, so you're all trapped there until every bad guy is dead.
There are a number of buggy spots from where the bad guys can lay down murderous barrages of bullets and you can't even see them to effectively return fire. The most problematic is the very top corner of the building and some boxes just to the right side. You'll have to either fall back or sally forth to dislodge any guys who start camping there.

Again, you have two options here. I suggest you read on before making your first attempt on this level.
This is a big and well-defended level. Anyone who approaches the front entrance (default starting location) will raise the alarm and immediately take heavy fire from a sizable criminal garrison. Then more gangsters will start to flow in if you don't disable the alarm. Disabling the alarm requires a battery pack one of your Rebels is carrying as well as a code you'll find on a note somehwere in the building. Oh, and you'll only get to the alarm panel by fighting through a hallway filled with crooks. Many of them are carrying shotguns.
If you accept all the side missions and send all your Rebels through the alternate entrances you can easily sneak through the corridors and set the bomb which is your main mission, grab all the secondary objectives and make off with some good loot. There's a lot of money to be made here if you are thorough in taking down the bad guys. They aren't hard to kill or arrest if you approach from any direction other than the front entrance.
Navigating the locked doors will be a maze of corridors filled with small groups of guards as you find notes with codes on them. Stick close to your fellow Rebels and you shouldn't have a problem. Buddy saves will help out in the tight corridors.
This will be the last level where you can use lockpicks. You may want to bring a lot of them to help move quicker and quieter.

Your archenemy is teaming up with the local pagans. Now you have to infiltrate a veritable fortress packed with all manner of nasty creatures who live in a squalid commune littered with animal carcasses and decorated with human skulls. This is a hard level.
There are no locks to pick, though. There are only two locks on the entire map, both electronic key codes blocking your access to a side objective and a very expensive loot pile. This is a great place to get thousands of dollars for the late game.
You'll be facing down a healthy mix of petty thugs and orcs in here. If the bell chimes five times (around turn 32?) there will be another 12 or so baddies reinforcing their already formidable numbers ( about 80). Your experienced, well equipped Rebels shouldn't have too much trouble so long as you stick to cover. A small amount of gunfire won't automatically put the whole compound on alert.
Your target, Alphyna Bering, will be patiently waiting for you no matter how long you take or how big a ruckus you cause. Go nuts.

The Licky Spit Casino is a fun challenge. My biggest piece of advice is to leave a rookie to cover 'Eagle,' the kid monitoring the security cameras in the outbuilding. Use your veterans to quietly sweep the main building.
This is the last time you'll be using silencers, so don't worry about breaking them. Rifles and shotguns will also come in handy if when things get loud.

Okay, this one may be tricky, but you should have six well-equipped veterans to take down the jerk who who's been ruining this town. He knows you're coming, so there is no stealth here.
My recommendation is to equip everyone with full armor and a ton of flashbangs. Have two guys with shotguns charge up the middle to spook Zuev while your four riflemen swing wide and work on his goons. Your armament by this point should shred the criminals with minimal difficulty.
Zuev will easily snipe any of your Rebels not behind full cover. Blitz his position to force him to retreat.
Move through the garden and around to the back of the mansion quickly to cut him off from his helicopter and blast him with your remaining flashbangs.
If you do this right you just won the game.

I think Rebel Yell is the final act of the game's story, following the last scene before the credits. You have just four Rebels who must gather equipment as they fight and flee for their lives. Survive to turn 37 or so and one more Rebel will find her way to you and aid in your valiant last stand.
Enemies will quickly become more numerous and better equipped. You need to focus on grabbing pistols, rifles, ammo for both, armor and rebel points. It's best to stay together, or at least teams of two to grab more items while the firefight goes on.
Stick to cover and hope for the best.

utitivivi mapped out the cone of vision for the bad guys. Hope this helps you avoid detection.
The red squares will raise the alarm. The spaces next to the red squares will give them the '?' status, and the criminal will start looking for your Rebel. This can be useful for luring them away from their regular path or main group when done correctly.

Always stick to cover. Always.

Remember that in this game you can pick up and hide bodies to avoid raising the alarm. It'll burn AP as your Rebels move slower and have trouble hiding while carrying a corpse.