By following this walkthrough, you will get get all trophies/achievements in the game. Most of the trophies/achievements are unlocked automatically, while for some, you need to interact with specific objects. "The first Killed Alien" and "Knock an Alien with the Bat" can be achieved anywhere aliens are present. As for "Revolver Drum full of Ammo," you must have a full magazine with six bullets.

https://www.youtube.com/watch?v=xid79299kD0