Hollow

This is likely going to be your first achievement and is available after about 15-20 minutes of starting the game.

When you get to the control room (big circular room) you have to kick the power back on. This will power the elevator and a nearby console, where you can save. There's also a weapon by (in) the console, so pick it up, then as you approach the elevator you will spot your first enemy. Simply dispatch it, but be careful because your ammo is limited.