Thank you for playing! Taking away blocks sounds like a good way to spice it up. Didn't think of that! Maybe I could've made the cooldowns a bit longer to incentivize cycling through blocks a bit more. I was just a bit scared of the game being too hard so noone finishes it.
I think a good way to ensure better balancing would be to ditch buying blocks mechanic and instead give the player a full set of blocks at the start and then allow to change one block for another at Kaela's. That way there is less variations to worry about when smoothing out the difficulty curve. I'll think about it later some day!