Thanks, the time constraint was a bit daunting. I never really thought about the inventory after I set it to F, the mouse attachment is an issue I'm hearing about for the first time and I'll look into it. You have to press R to breathe whenever the lungs flash yellow, pressing it late will cause you to lose oxygen. As for finishing the level, take out the target, pick up the body with E, stand next to the door, and press E to open it to go to the next level. My tutorial this time around was lackluster and the controls are a bit confusing, sorry.