Well, you know how there is a brass balls achivement! well wat about silver or gold? i have some ideas
Silver balls: beat game on hard difficulty using only 1 plasmid on enimies
Gold balls: beat game on hard difficulty using only a wrench+plasmids.
If you have any other ideas i would like to know if you have some or if you want more!
Platinum Balls: Beat the game with your bare hands.
I like skill achievements like the Brass Balls I am not a fan of the collecting achievements you see in many games like the audio diaries.
Of course my favorite has to be the Simpson's game it says "Press Start to begin" and you get an "Achievement Unlocked" for pressing start.