First Portal had a ton of timed puzzles but many players found them really frustrating so in Portal 2 the developers toned them down by a lot and I think it's a lot more enjoyable game since you can take your time to solve the puzzles.
Kinda related to this but I really hate how much traversal gimmicks there are in DE. In addition to jumps, climbable walls and monkey bars every room has cannons firing fireballs, lightning arcs, purple goo, tentacles or some other nominal obstacle. They don't make the game any more challenging, just annoying.
I don't know what's so bad about just walking through a room or corridor to the next area and have a little breather.