I found Radec to be easy. The hard part was getting to fight him while you get swarmed by generic soldiers.
Stand on the balcony, back to the corner.. Wait for him to teleport infront of you and unload. He'll disappear.. Turn around briefly and he'll reappear infront of you, so give him some more lead sandwiches.
I prefer the shooting mechanics of KZ2. The recoil was unforgiving if you like to spray, which I can see a lot of people hating, but popping off bursts and taking down enemies is satisfying. The build up to the last battle actually seemed intense on the harder difficulties.. Battling through waves of enemies while you inch up to the building was the highlight for me.
One complaint for me would be the annoyingly "jock" nature of your team. I wanted them to die after the 100th battle cry / trash talk.