@Guillaume

I guess. I mean, it's pretty obvious most of the time why you die in Super Meat Boy - for me, it's usually the fact that I didn't jump high enough or far enough to get over the spinning metal blade of death. Though, to @Secret_Tunnel's point, that's more execution than level-solving. 1001 Spikes has some moments where traps and hazards come out of nowhere, but once you know where they are, it's a matter of figuring out how to avoid it.

Which...honestly isn't that different from Super Meat Boy, really. I mean, right? "On paper" I think the two games execution on tough-as-nails platforming is not that different, but man...playing the two games just *feels* different to me.

I get different feels, man.

So this games gets hard about 2/3rds of the way through, eh?

Levels 1-20: Never died more than 25 times in a stage.
Level 21: 82 deaths
Level 22: 91 deaths and counting.

Yep, World 4 can be brutal. That's where you start to get the few instances of needing to nail the execution as well as solving the puzzle.