Rat Hacker- Hack a rat. This is the earliest achievement you can get. Rats that can be hacked have a square around them.

Bonk City- Finish the final level of the game and it will unlock.

Raccoon Roundup- On the last level, right at the start, they'll be graffiti on the wall with the same icon as the achievement. Press T to interact with it and you'll get the achievement.