I like chill games like this where there's just enough of a feeling of progression to keep you going! It's a difficult balance, but I think you made a smart design choice by using the upgrades to make gameplay changes visible to the player, and tying it to an in-game currency gave an added sense of reward. I definitely preferred using mouse controls because it was more responsive. I think keyboard controls could've worked if the ouroboros moved as fast that way as could be achieved with the mouse, but maybe you tried that and it was unwieldy, so I don't know. It was short and I can see how you could keep developing the concept, but it felt complete for a jam game, nice work!

Very good gameplay loop! It is a smart mechanic that I enjoyed. I think you should add a big bonus for if you clear all of the shapes off!

I played this game for quite a while, and if I hadn't forced myself to stop, I would have spent hours playing it. Your game has a very original concept, wonderful fluid gameplay, and a skill tree that, just by appearing on the screen, makes me excited to see what I can and can't buy. I admit that playing with the keyboard isn't as satisfying as playing with the mouse, but it's still fun and doesn't spoil the experience at all.

I really want to see this game with more upgrades, more skills, and different combos, as the guy in the comment below mentioned.

~ Congrats on creating this jewel!

I like the concept and the vibe it gives off together with the music, very relaxing! 
Playing it with a mouse is 100x easier than with arrowkeys.

Very fun game, i was able to win it! It would be nice if combos had a different feedback than regular captures, at times i was able to get several shapes and i felt excitement and i could see big numbers but some feedback from the game would be nice.