Had a bunch of fun playing through this, it becomes an exercise in physical endurance after a while! Managed to get to level 62 before my wrist and fingers had enough!
The art is great, and I gotta say, I think this is the best 'Fist of the north star' like game I have ever played.
The announcer adds a level of immersion, love it.
Some thoughts on how I'd structure it:
(Skippable) Intro: Shows dude, then good guys (at least 5). Introduce mechanics. Show 'fodder' bad guys (at least 5), then a partially obscured view of floor 100 boss.
Perhaps a boss level every 10 levels or so? After boss level, press a button to continue, to rest fingers and wrists for a bit (or allow call of nature!). Show dude doing weights, having tea with granny (pinky out!), petting the dog, etc while waiting for button push.
Then there has to be an end game. Does he end the darkness by killing Cthulhu?
Anyway, whatever direction you guys choose, I'm looking forward to have another 'punch' at it!