I thought it was a tad bit harder than Chaos but only in the fact that you seem to drop from full health to none from alot less hits which lead to playing the game a bit smarter than running and gunning. Infact, it was the first time I ever made extensive use of the sniper elemental shot. But like bluntman said, elemental shot machine fire is your best friend in any mode. Also I found that elemental shot shotgun wind was handy as well when you got caught in a swarm of enemies. A shot on one would daze the others from being able to shoot allowing you a chance to mow them down or get to cover.
Originally Posted by darkboy1200
I think the final boss fight just seemed a little harder on Hell Mode
Oddly enough on Hell Mode, I got him down on my first try when it took at least two or three on other modes (once I learned the fight). Now getting to him was a challenge..