Cool concept once you grasp the fusing aspect.
From there on you really want to get more and more upgrades.
And once you die you get to keep 1 of your best cards, feeling like you still make some progress.
It was a blast to play for quite a bit!
Great job creating and submitting a game!
Edit: I wasn't sure how to get money to buy new cards. But after watching your playthrough I see that there was a sell-section in the shop. And that were some secret upgrades. The secret upgrades are not as obvious - maybe putting hints for the combinations in hard to reach places is an idea. Was cool to watch - thank you for sharing your thoughts.