Hey, thanks so much for the detailed feedback. Really appreciate you taking the time to write all that out, especially with a screenshot to back it up.
Good news: pretty much everything you flagged has been built. You'll be able to bail out of a run instead of waiting to lose it out (Abandon Run), there's a panel showing every upgrade you've picked so far, flat % upgrades got dialed back in favor of more interesting cards, "air wave" rounds where enemies ignore your maze entirely are in, bosses now drop a special equippable relic every 10 waves (works in Endless too), and there's a proper gold sink for the late/endgame so surplus gold doesn't just pile up doing nothing.
And the hybrid tower idea (fusing two maxed towers into one) is done too. It's turned out pretty deep: which tower you fuse into which changes the result, so there's a lot more to it than a simple combo system. I'm testing it right now before I repackage the build.
Still on my list: an auto-pick option for upgrades so the late game isn't just clicking through cards once your maze is built. Good call, just haven't gotten to it yet.
I'll push the updated build once testing wraps up and credit your feedback in the changelog. Thanks again! This is exactly the kind of input that makes the game better.
Alberto