"Final Boss"? Ha! I AM the final boss!
There was no challenge at all with this build and it was my first run. Suggest a mechanic that enforces a minimum party size, or more obvious benefits to doing so.
The minion Quirk is overpowered with even a single Bumpster, especially in maps with small alcoves. Suggest heavily nerfing it (quantity cap?) or removing it entirely.
Suggest making it clearer that there are Stat caps, and if the Stat-boosting quirks boost past them. In general, while it works just fine with the short game loop, the game doesn't explain anything internally. Even learning what the Bumpsters' names are requires purchasing them, without the hovertext option Quirks and Stats have.
It was short and really fun though. The chance-based Beyblade battle mechanic is underrated and I think it works great here.