Sorry, it took me so long to respond - I was "offline" for a week.
So, thank you for great feedback! While, of course, it might be "not your thing", all points you made are very valid and I'll take them in to consideration while making new level.
Since a couple of problems arise from challenge level, I should note that it was a level made during the gamejam, so it is quite a long one on purpose & has no enemy types, which were added later. I left it unchanged as a nod to early players. I'm also a fan of presenting new challenges gradually, so that new player won't be bombarded by various obstacles, yet, I get that this way the presentation of the "fighting" side of the game is lacking.
My next step will be making a set of shorter level set with hand-positioned obstacles, so that should solve the need of checkpoints and I will be able to make it more tense, since there will be less need to give player a break in between trap-clusters. I'll try to work on enemy AI/boss fights to add more to the "fighting" part of the game, too.
Well, I got bored/annoyed after about a minute and a half but that's because I'm not a big fan of this sort of game. I really thought I'd enjoy it when I saw the GIFs, though.
I think my main issue is that the game starts out like a Flappy Meat Boy game and doesn't add enemies for a few screens. By then, I was already disappointed that there was so little combat, since the moves you mention in your post weren't even being used.
Strangely, I also didn't feel any excitement. Super Meat Boy wasn't my type of game either, but I at least felt tense. Maybe the character should speed up as they move through the level? I'm not sure.
Personally, I also wish there were checkpoints in the normal mode. For endless, it makes perfect sense to see how far you can get before dying. In the normal mode, though, I found the first level much longer than my "Do I really want to play through all that again?" limit.
The controls work really well. I think the shuriken could be made to show up a bit more, and the fire shouldn't cover up the Music button, but overall I think the game is artistically and technically quite well made. I'm interested to see what fans of flappy games or meat-boy-like games will think of it.