A very dark game with good horror elements in it. Most of it isn't bad, but you tend to slide around a lot (mostly in mid air), you don't have check points in the middle of the game, and getting the good ending can be HARD.
Speaking of which, you have to NOT KILL WITH THE GUN (deflecting with the shield and shooting destructible walls is fine), to get the good ending, and that includes Uzaza. To beat Uzaza with no gun, you have to touch the 3 lightning orb things, then something stabs him for you.
SoyLung mentions the other 2 medals.
One last tip: pressing Z restarts an area (but has little practical use since those red item things warp to you if you find them after losing them in a death trap).