Really awesome game. The auto aim, and the footprints go really well into making this just about having fun, and not frustrating over getting lost and aiming (without mouse). It's very completionist friendly, rewarding the player well for clearing the whole level before moving on. It's just really good. And awesome music.
Personally, I was never short of ammo, but health... I gained an extra heart at one point but couldn't fill it. Ended up dying the second I walked through a door (usually go in guns blazing, but this one already hit me before I noticed.)