I can’t remember an old game’s name but I know what was the last lever

So guys, I tried to rememorize an old game I used to play but I couldn't remember it name also I couldn't find it by searching about it specifications. All I can remember is it's a game where you can play as a monster then as a human. And the last mission is a helicopter tries to kill you so you have to destroy it by throwing barrels at it with your monster shape. It's an FPS game.

*sorry about grammar, English isn't my language*