Yeah, so, in WH40k "Space Marine", you fight Orks (who can be pretty god damned tough) and then eventually Chaos Space Marines, who turn out to be hard as NAILS, just like they should be. They're regular Space Marines (walking man-tanks of righteous fury) infused with the nastiest daemonic shit the universe can pump into their veins.
So, the Chaos Warband is called the "Chosen of Nemeroth"... those who follow Lord Nemeroth, which tends to mean that if he's got a whole Chaos Warband following him, Nemeroth is gonna be a pretty bad ass dude who doesn't take shit from anyone. When you finally come to fight him it's a pretty cool looking show-down, but I think things start to go a bit wrong when you realise that for the first part of the battle he's just a glorified spawn point. When you fight the Ork Warboss earlier in the game, sure he's a cakewalk, but it's quite satisfying when he's smashing open walls to let his horde into the boss room, whilst you try to take him down, you've got his grunts nipping at your heels, he feels like a real boss, as in a leader.
Nemeroth? Like I said, he starts as a spawn point with some sort of Warp-shield around him. You kill his dudes in waves, a battle where you have to utilize all your skills and weapons, taking cover and taking pot-shots for some enemies, getting stuck in with your Close Combat Weapons for others. Then when you finally clear them out, what happens?
Nemeroth drops his guard and you get your chance! For a QUICK TIME EVENT. The longest Quick Time Event you've seen. Which literally culminates in PRESS X TO POP NEMEROTHS HEAD LIKE A GRAPE.
http://youtu.be/uFsPUrs7LKk
So lame, because as far as Lore is concerned, Nemeroth is rolling out in a full set of Daemonic "Terminator" Armor. Which should make him just about as hard to kill as The Governator himself, with the strength to crush you like a piece of paper if you get too close... But no, Captain Tit(us) is once again totally OP. Not because of his DIVINE FURY, or his impressive combat prowess, but because he's Captain Titus, an Ultramarine. A member of one of the most boring factions in Warhammer, always seemingly guaranteed to win, without having any kind of personality or losing any battle they ever fight. I mean, come on, right after killing Nemeroth, Titus sacrifices himself in a warp explosion the size of a football field and still survives without a scratch.