actually i found doom3 to be more boring and repetitive. I have played far cry three times from start till the end now and i must say , each time i notice something different or new about the game. The graphics , the environment , the gameplay are rather exciting. Agreed HL2 has a much more interactive environment but Far Cry has more stuff in its environment that you can actually use and not knock over.
Cruising through the river , fighting other gun rigged boats , trying to knock down snipers and rocket launchers was hella fun , as was using a handglider to go from one mountain to the other.
As for the fugly monkey primate mutants , they are rather easy , shoot them before they get close to you coz they make a leap at u when they are close enough. The dumbheaded rocketlauncher rigged mutants are more harder to kill but they are stupid and if u hide from them , they will just come and stand next to you.