1. How every single shooter now uses Health Regeneration. Resistance had a great, original, health system which is a health bar/regeneration and you pick up health packs. They are guilty of relying fully on regeneration now.
2. Another one Resistance 2 is guilty of. The 2 gun system in FPS games. You can only have one main gun and one pistol, or 2 main guns. The original Resistance let you have every gun at the same time.
3. Having guns in online games that are totally cheap as hell. Like the Grenade launcher (aka noob tube) in Call of Duty 4, that made things annoying. And the M16 is way overpowered in CoD4 because its a 3 burst gun. The Rocket Launcher in Halo is another one. I hope theres no cheap guns in Killzone 2 but I have a feeling the Grenade Launcher will be.