Super cute little game with lots of interesting upgrades! One bug is that I've gotten pretty far into the game but suddenly the upgrade, rebirth and card icons all disappeared! The options icon also went away so I can't try to change any settings to see if it gets fixed...
Other than that it may be nice to add an upgrade that makes it so you don't have to hold the mouse down to hit and collect, as it starts to get painful for your fingers after a bit ;^_^
Overall super fun and I'm excited to see how the finished game comes out!