I am writing this guide to document my experience with earning achievements. I will be organizing similar achievements, so feel free to CTRL + F search the name of the specific achievement you wish to find out about.
I will also provide general tips and things I've noticed about the game as I go. Though, do note that I will not be writing tutorials on things; I expect people to have already started their journey in this game.

Disclaimer: I am no expert in this game, nor do I profess to fully understand the design of the game or how things work. I have not gone out of my way to test things thoroughly.

Welcome to the Colony!
Someone is playing our game??
Simply launching the game will give you this achievement.


Circulatory System
Complete 1 run
Start a run and finish it, win or lose. You should get this when you start, as you are thrown into a run before getting to the Colony.


Dark Forest
Play a run on Dark Forest
The standard map that you play on before unlocking any others. not much to say, apart from noting it has 24 waves total and 2 bosses.



Maple Ruins
Play a run on Maple Ruins
This map, as the name suggests, takes place in ruins around a big statue. The enemies and bosses are more or less the same, with the only new addition being bats with a wind-up charge attack.
However, the twist with this map (aside from the extra geometry) is the statue provides a buff roughly every 20 - 30 seconds. This is denoted in two ways; when the buff is active, squares around the map light up blue, and the statue will be holding a golden ball. When inactive, the squares will be red, and the statue's golden ball will be covered up.

The buff does the following:
• +100% movement speed
  
• +100% attack
  
• +25% cooldown
  
• + 100% area
  
• + 100% knockback
  
• + 100% armour
  
• + 1 projectile

Happy Lil' Forest
Play a run on Happy Lil' Forest
This map is smaller than the previous 2 maps, and the enemies have some variation, mainly smaller, much faster spiders to start, and flytraps that shoot fireballs at you. Both are deadly on higher difficulties.
The upside of this map is that it's shorter than the previous 2; 16 waves, and only one giant flytrap boss that doesn't move, but does fire a large mortar shot at you.


Hallowed Haven
Play a run on Hallowed Haven
Similar to Happy Lil' Forest, except that it has more geometry, 2 flytrap bosses, and 4 portals in the corners that you can use to move around (with a cooldown)


Moonbeam
Play in the Dark forest 20 times
Self-explanatory. You'll get this just playing, likely.


Cast Out
Reach Wave 13 in Hallowed Haven
Self-explanatory.


Sunbeam
Play in the Happy Lil Forest 10 times
Self-explanatory.


Strike
Obtain True Survival
During a run, the game will open the exit door at around the halfway mark, allowing you to leave early with what you have. Leaving would mark your run as a Survival. Staying and completing the whole run will result in a True Survival.


Merchant
Obtain a True Survival
See previous achievement.

Fungi
Defeat 1000 Moles
Self-explanatory. You will get this naturally.


Blood Sucker
Defeat 5000 spiders
Self-explanatory. You will get this naturally.


Chirp
Defeat 2000 birds
Self-explanatory. You will get this naturally.


Wingspan
Defeat 10,000 Bats
Self-explanatory. You will get this naturally.


Poison Spikes
Defeat 2000 Venus Fly Traps
Self-explanatory. This one requires a bit more effort to get, as, only GREEN flytraps count towards this, and because they do not move, you need to go out of your way to murder them. Still, this isn't painful to go for, and did not require me to grind it out.


Mandible
Defeat 40,000 enemies total
Self-explanatory. You will get this naturally.


Fire Cracker
Defeat 10 elite enemies
Elite's are slightly bigger variants of enemies, usually with some colour palette differences. However, they are extremely common, and you will get this easily.


Zapper
Kill a boss
Bosses are the very large enemies that have dedicated health bars. Since you need to kill them to finish waves, you'll get this easily.

I'll take this time to describe the three bosses:
• Giant Spider: chases you down, and is not affected by knock-back. Stay faster than it, or disable its movement with Zapper(After you unlocked it, of course).
  
• Giant Frog: Slower than the spider, but has a telegraphed charge attack that does high damage. Stay out of the red path of destruction it takes. Do note that the charge attack does also hurt other enemies.
  
• Giant Flytrap: Can't move, but will still hurt you if you get near. Occasionally launches a large fireball mortar shot at you, so keep moving.

Acid Spray
Equip 6 weapons in a single run
Self-explanatory.


Life Seed
Reach Lv. 3 with Bloodsucker
Self-explanatory.


Gust
Reach Lv. 3 with Velocity
Self-explanatory.


Echo
Reach Lv. 8 with Bees
Self-explanatory.


Sonic Boom
Reach Lv. 8 with Zapper
Self-explanatory.


Honeydew
Use Banishing Blow 10 times
Banishing Blow is your 'Ultimate', so to speak. Using it a cumulative 10 times is all it takes.


Skill Tree
Reach Lv. 9 with any rare or higher active skill
Self-explanatory. Note that skills with green backgrounds DO NOT count, only blue, purple, yellow, and orange.


Velocity
Equip 5 projectile based weapons in one run

Projectile based weapons are as follows:
• Rock-et
  
• Acorn
  
• Poison Spikes
  
• Firecrackers
  
• Mandible
  
• Stinger
  
• Acid Spray
  
• Leaf Shuriken
  
• Venom Spit
  
• Bees

it may take some luck (or rerolls) to get 5, but you can easily get this done on a low difficulty.


Eruption
Equip 3 Dash Skills in a single run
This achievement is a little unclear, as there are both Weapon Skills and Passive Skills related to Dash. As I understand this achievement, You must get either three weapon skills or three passive skills. I have tried to get this done with 4 Dash Skills, 2 weapons and 2 passive, and I did not earn the achievement.

Here is a list of Dash Skills
• Acid Spray
  
• Molt
  
• Scurry
  
• Rush
  
• Sonic Boom
  
• Leaf Shuriken
  
• Concussive Blast

Bug Brained
Build a Skill Tree
Self-explanatory; once you unlock it, build it.


Gatherer
Build the Carpenter
Self-explanatory; once you unlock it, build it.
This will also allow you to recruit and use a 'companion', the Carpenter Antonio. He wield s a big hammer, and will do an AOE attack ever so often.


Sharpen
Build a Gym
Self-explanatory; once you unlock it, build it.
Unlocking this will also allow you to recruit Ironchad. Ironchad will regularly run in a straight line, and damage anything in the way. if he hits a wall early, he will be stunned for a few seconds.


Carpenter, Decoy, Villager Homes, Precision
Reach Colony Enrichement Level 1, 2, 3, & 7
Enrichment is increased by the buildings / decorations you put down in your colony; however, as far as I can tell, all decorations give the same / similar amounts of progress towards the next level of enrichment.
You also need to spend Flower Coins on upgrading your capacity for buildings / colonists. This is not a worthless venture, as each level of enrichment gives +1% towards your stats, with higher levels affecting more of your stats. Worth doing early game.

Acorn
Destroy 20 acorn trees
Acorn Trees are small trees that spawn every so often on any map; destroying them drops one of the following items:

• Flower Coins - gives a small amount of Flower Coins.
  
• Banish Charge - Fully fills your Banish Meter.
  
• Magnet - Magnetizes all Flower Coins & XP crystals to you.
  
• Bug Spray - Instakills all non-boss enemies. No exp drops, but chests will drop from elites.
  
• Health - Heals you for 10 health.
  
• Dice - Gives you one extra Reroll.
  
• Zapper - Freezes all spawned enemies in place for a few seconds. Newly spawned enemies are unaffected.
  
• Clover - Increases your luck by 1% for the run.

Note that the game will also indicate if there is a acorn tree off screen, with a brown-gold acorn and arrow pointing towards it.


Lucky Clover
Receive luck from an Acorn Tree
Get a clover to drop from a tree. Easy.


Acorn Tree
Destroy 750 Acorn Trees
Self-explanatory; You'll get this naturally as you do want to destroy these.

Crescent Moon, Eclipse, Blood Moon, Sun
Unlock Crescent Moon, Eclipse, Blood Moon & Sun Difficulty
First off, difficulties are unlocked only for the map you did a True Survival on with the previous difficulty.
To give an example, If I want unlock Blood Moon difficulty on Maple Ruins, I must start a run on Eclipse difficulty, ignore the early escape given halfway through the waves, and complete the run. This will unlock Blood Moon difficulty for Maple Ruins only. Note that Boss enemies must be killed for the run to end.
Each difficulty increases the health, speed, and damage of all enemies. With good weapon choices / combos, you should have no problem with any difficulty below Blood Moon.
However, Blood Moon and higher is when you need to buff up like crazy and plan out what weapons you need to get. The reason for this is mostly because at these difficulties, enemies will have such high move speed, that they can simply run you down and kill you.
I'll get into what I recommend you do for each character in their specific achievements, however, here are some general tips and recommendations:

• The gym allows you to gain permanent upgrades that are applied to all characters; buy everything.
  
• The gym also allows you to 'workout' for a fee; basically giving you a free level up before you start your next run. Note you can do this multiple times, but the Flower Coin cost is exponential.
  
• The merchant allows you to buy a power-up that you can use whenever you want. I don't recommend this, because the power-ups aren't really good enough to be life-saving,especially for their cost, and that you are limited to one.
  
• The cafe allows you to buy 'coffee', which gives you extra buffs for your next run. In general, XP gain and Move speed are your friends.
  
• when you get villagers in your colony, lure them in one place by trying to break a rock or something, and then talk to any with exclamation marks over their heads. they will either give you Flower coins, or a permanent buff to one of your stats. The villagers reset after every run, so check often.
  
• Unlock the Tempo Skill and ALWAYS get it. Shorter cooldowns on everything is an amazing thing, but especially on Zapper and Leaf Barrier.
  
• Stick-fu, Leaf Barrier, and Seed Bomb are likely the best weapons once upgraded, and even better once gotten to Level 10.

Here's the general setup I had that got me through the harder difficulties:
Weapons - Stick-Fu, Leaf Barrier, Seed bomb, Life Seed, Firecrackers, Zapper
Passives - Sharpen, Repel, Tempo, Camoflage, Echo, Hind-Legs

NOTE: As of this patch, there is no achievement for unlocking Supergiant difficulty, but you must do so for character related achievements.

Stick Fu
Play as Tato in an Arena
Simply finish a run with Tato, win or lose.


Camo
Reach Lv 25 as Tato
Self-explanatory, earn enough XP crystals to level up.


Tato Mastery I, II, III, IV, V, VI
Obtain True Survival as Tato on Normal, Crescent Moon, Eclipse, Blood Moon, Sun & Supergiant

Tato is your average beginner class; a good weapon, good Banishing Blow(BB), ok character perks. Starting with Stick-fu means he can hold his own until you level him.
Because his perks don't affect most weapon / passive skills, it's pretty free form what to get him to where he can survive in higher difficulties. I do recommend upping his move speed on Sun & Supergiant, but that's about it.
The best skills for him are the general ones, meaning stick-fu, leaf barrier, Tempo, etc.
He'll do fine on any map as well, so long as his movespeed is good.

Rockin' Roxy
Play as Roxy
Unlock Roxy and enter the colony as her, and you'll get this achievement.



Rock-et
Play as Roxy in an Arena
self-explanatory.



Flower Coins
Reach Lv. 20 as Roxy
self-explanatory.


Roxy Mastery I, II, III, IV, v, VI
Obtain True Survival as Roxy on Normal, Crescent Moon, Eclipse. Blood Moon, Sun & Supergiant
Roxy's starting weapon not being AOE can be a problem, but the fact that it ricochets and increases damage on the ricochet is a pretty nice trade off. Her perk increasing projectile speed is good as well, so long as you take it into account when levelling. Pick mostly projectile based weapons, but keep a Leaf Barrier to keep enemies from getting too comfy near you.
So long as her move speed is increased, Roxy will also play fine on any map.

Mighty Mighty Green
Play as Mighty Green
Same as Roxy's; unlock him and enter the colony.


Leaf Shuriken
Play as Mighty Green in an Arena
Self-explanatory.


Tempo
Reach Lvl. 20 as Mighty Green
Self-explanatory. I will say that this should be your absolute priority to unlock, as this is probably the best skill in the game.


Mighty Green Mastery I, II, III, IV
Obtain True Survival as Mighty Green on Normal, Crescent Moon, Eclipse & Blood Moon
Surprisingly, Mighty Green only has achievements up to Blood Moon.
Mighty Green is all about dashing and moving; his starting weapon only works on a dash, and his perks gives him faster move speed, shorter dash cool-down, and more distance covered for the dash once levelling him. Going for dash / movement skills is a no-brainer, but the general AOE weapons / skills are still a good idea, because movement can't save you if you have no safe area to get to.

Ran-Cid Stench
Play as Cid
Same as the Roxy & Might Green.


Stink
Play as Cid in an Arena
Self-explanatory.


Repel
Reach Lv. 20 as Cid
Self-explanatory.


Cid Mastery I, II, III, IV, V, VI
Obtain True Survival as Cid on Normal, crescent Moon, Eclipse, Blood Moon, Sun, Supergiant
Cid's starting weapon seems like a better version of Leaf Barrier at first glance. Enemies walking into you will simply die. However, the issue comes up when you can no longer one-shot enemies who walk into the AOE of the weapon; the 'cool-down' of the weapon when hitting the same target is atrociously long. On higher difficulties, that means basically all enemies will just shrug it off and kill you anyways. Solve this with higher move speed or quickly get a different weapon.
Thankfully, Cid's perks are pretty good; bigger pickup area is good, but larger area when levelling means that any AOE affect becomes a screen clearing monster.

Queen of the Colony
Play as Queen Beatrice
Same as the previous characters.


Stinger
Play as Queen Bee in an Arena
Self-explanatory.


Queen Beatrice Mastery I, II, III, IV, V, VI
Obtain True Survival as Queen Beatrice on Normal, Crescent Moon, Eclipse, Blood Moon, Sun & Supergiant
Queen Beatrice suffers from a similar problem to Cid; she just can't kill things on higher difficulties without having another weapon to back her up. Stinger is a great single target, piercing weapon, but in a horde type environment, it doesn't hold up. Pay for coffee buffs or workout fees so she starts faster / with more skills.
The same general weapons apply here, though her perk of extra projectiles does make more single target attacks viable.

Leeps and Bounds
Play as Leep


Nice Dice
Reach Lv. 20 with Leep


Leep Mastery I, II, III, IV, V, VI
Obtain True Survival as Leep on Normal, Crescent Moon, Eclipse, Blood Moon, Sun & Supergiant
Leep is a terrible character. No 2 ways about it. -20% to everything means investing more into making him survive on higher difficulties. The extra luck only affects the chances of items dropping from acorn trees and the rate of rarer skills to be found. IMO, this is not a good trade off.
If you want to play him on higher difficulties, you have no choice but to heavily invest in workout fees and coffee....
But there is something. I'm pretty sure it's a bug, so I don't recommend relying on it, in case it's fixed. But for those that want to know, Camoflage currently makes you permanently invincible on Leep. do everything within your power to get this in a run.
But without the above, the same general setup will work for this character, like it does for any other.

Hopefully This was all helpful in earning your 100% in this game. Thank you for checking out my guide!