Loved how fitting the music was to the gameplay and also how random certain weapon upgrades were. One second I'd have certain upgrades which I could see myself use all game, just to then have that change and also change the way I play the game. Such things gives the player the oppertunity to be creative and also have a variety of set options to consider when you do certain "plays"!
It's also very refreshing to consider the not so common angle/perspective which the game is played in, doing so that you rework your process from the typical 1st and 3rd person games!