Overall fine, nice job. It fits the anger theme rather well without going too far with frustration. I do find some spots might need some spacing out though, as Lightvayne pointed out, mainly around screens 07-08 I think, although that one does seem harder than it actually is maybe. It is pretty tough at a first approach, atleast for me.
Another complaint would be the big chomp's hitbox, which is a bit misplaced to the top:
That makes passing through the chomps in screen 07 (not pictured) harder than it needs to be, atleast for super mario.
Also nitpick time, but this guy's fireballs are a bit too misplaced to the left:
I know that's horrendously minor but whatever V:
It's easy to fix if you want to, just have someone shift the spawning point of the flames a couple of pixels to the right (I can probably do that if you want). Also is that burning guy used anywhere else? I don't think we need the fireballs to shoot upwards in case it isn't, just to cut on the amount of extended sprite slots used at the same time. Some of the fireballs are sometimes not spawned due to lack of free slots too.