Something to look at

[Soul Walker]

1) a lot of later levels have it where if you screw up once you have to start from the beginning which is extremely frustrating considering how difficult a part can be.
2) Some level Design can be flawed to the point where they can be mind numbingly hard, like, I wanna Be the guy level hard. (Youtube the gameplay)
3) Hit detection can be very choppy from time to time, from a point where I never touched the spike to the point where I die from one pixel touching the spike Like how megaman 9 was.
4) Bring a Towel, the speakers have too irregular of a pattern no matter the song it could realy screw you over that they would smack you on the bounce pads going backwards, finally finished after about 13 minutes which felt like forever

[rory]

Yeah, Bring A Towel is... sloppy. Bad. And I agree with the backtracking as well. Unnecessary, wastes time, etc...
At least I figured out how to break Reverb Nation, can't do that with Bring A Towel.
None of the levels are even close to IWBTG though. Also, that's a bad comparsion, because IWBTG is not that execution-hard compared to lots of other platformers. It's hard because of the surprise traps, though it's certainly not an easy game by any means.