Unreal is a great FPS due to clever level design (except maybe the first levels), weapons (almost all weapons are very unique) and IA (ennemies will dodge, retreat, and take or close distance depending on their weapons). It is a long game (count 15 - 20 hours with expansion). I would advise playing in Medium difficulty, even if you are a good player, not so much due to difficulty of the game (harder than most of nowadays FPS, but not that hard) due to the high level of HPs of enemies in Hard which can make battles tedious - especially at the beginning when you don't have the cool weapons.