I'm ashamed to say I tried the game late at night and had to forcibly tear myself away from it! Just a couple of QoL things to point out:

The amount on the slot machine is often obscured by the coin particle effect so it's hard to tell how much you're making.

The cental button on the level up screen overlaps with the bottom of Big Dollar's hitbox - might be good to lock input for 0.5 seconds or so upon levelling up to prevent misclicks.