Miracle aim enemies. The kind that can see you from 200 meters and shoot from the same distance. Sniper: Ghost Warrior and to a lesser extent Far Cry (at least in Far Cry you had to shoot at them first).
Who care how good the graphics are. It's the art design that matters, but good graphics to realise this is also welcome. So apart from the inside of the alien ship (which was its self had a confusing and unintuitive layout) from the original Crysis, it was pretty bland. That's why something like Super Mario Galaxy or Uncharted 2 are the best looking games, combining well thought out art design with a good engine.