I think this game concept is SO cool and unique! You really found something new, and that's awesome.
Heartbreakingly crashed mid-combo once and refreshing made me lose the moves I'd unlocked, so some kind of save feature would be really nice. Plus it'd be nice to be able to come back to the game without having to start over. Also, I feel like some more background elements scrolling past would help a lot with keeping track of how you and the opponent are moving.
I think this concept totally has the potential to be expanded on, and I'd love to see that happen. Maybe individual characters with their own move sets. Environmental elements that you have to play around or incorporate. Opponents with different properties. I mean, the core concept is fun enough you could do all or none of that and have a good game.