Complete the Episode's all 5 areas. Your score doesn't have to be 100%, so just play all areas at the first time. After you reached these achievements, you'll able to play the Episode's areas with unlimited gold, which is useful for testing weapons with their upgrades.

You need to destory every emenies on each maps. This is a bit hard in the 2nd and 3rd Episode. I think the best weapons are the Particle Ball and the Spread Rifle, but I'm sure it's possible the reach 100% with other weapons. You can test which weapons and upgreates are the best with the unlimited gold mode. Before you start the play, make a plan: you have 4 tries on an area. You shouldn't want to destory everything in the first one. So don't jut randomly shoot at the emenies, go for one side of the map, and try to destory them there. Closed range weapons are good for destorying dozens of blocks, a well-upgraded Spread Rifle for the rest.
I reacorder 3 videos, this might help you:
Episode 1:

Episode 2:

Episode 3:

Record a replay. For more information, read Proton's guide:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=325092371
Play a replay with another player. You don't have to get 100%.

You have to find a point at where you can jump off the map. If there isn't any (like the big cube maps) there is a rainbow ball somewhere, you have to touch it. For more, see Master Cheese's guide:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=355474715
You need to destory 500, 5.000, and 50.000 emenies with each weapon. For me, to reach 100% on every Episodes, I destoried like 100.000. You should play daily challgenes, and custom areas, these have 500-5.000 emenies. Tokeeto tells you some tips how to destroy as much block as possible:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=588533776
Play 1-10-50 daily challenge. You can play the same day's challenge more than once, it'll count in the achievement.

Create a custom room with the editor, then an area from you, or other players' rooms, and upload them to the workshop. (note: you can delete your uploaded rooms/areas, but be creative!). Kenzie's guide for creating a custom room:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=343420080
(if you see +1 secret achievement, that is a bug, this achievement was removed.)