I perfer shooting humans because your avatar is usually a human.
I like games where both sides are the same, you get basically the same equipment etc. Also the noises alien guns make often don't sound menacing.
That's what made me dislike the second part of Perfect Dark. Well that and the sniper gun that could shoot through walls was just soo cheap.
I also perfer games based on history in the battle genres. Gives you more sense of a high pitched war etc.








