I found TR to be pretty easy compared to Uncharted, it only starts to get difficult at the very end, but that was partly my own fault for using the shotgun when I should have been using the rifle. Nothing is nowhere near as difficult as the desert battle in Uncharted 3, not even close. What turned out to be the main boss fight was pretty lame... dodge dodge dodge, shoot... dodge dodge dodge, shoot... that's pretty much it. The very end turns out to be a button mashing exercise which was very unsatisfying to end the game on.
100%-ing the game was the most frustrating thing as many of the collectibles are very hard to find (especially the GPS Caches since they're so small and hard to spot) and it's a mini puzzle trying to get to each one. Couldn't find the final sun poster for the Sun Killer challenge in Cliffside Bunker at all, so I had to look that one up and it's so high up you'd never think to look there, no wonder I couldn't find it. :D