I love the fact that the old dragon's artifacts are esoteric, like a balloon, rather than traditional treasures.
The platforming is smooth, and the balloon granting double-jump and glide feels like it heralds a grand opening to another part of the game, should you continue to work on it.
I greatly enjoy the spritework, both the big and small dragons look good (the big one looks *really* good, in particular. That's the level of pixel art prowess I wish I had). I did notice the sprite layer does misalign with the background layer. It appears to be the result of freeform positioning on the upscaled viewport, as opposed to freeform on a 160x144 screen that is later upscaled. This happens to a lot of jam entries, so its a common tripping hazard in a lot of engines.
The musics been on loop the whole time I wrote this review. That tells me it loops well and is structurally pretty good.
At this scale, I could see screen-crunch being an issue with a fully developed powerup system. But, the GB Megaman games are *notorious* for screen crunch, so that crunch might be just how things go.
Even as just a prototype, this is a good entry for the jam.