Nice, with a few problems. First, balance is crazy. Why are there so many +83% gold multipliers? And runs can get annoyingly long. I'd make a way to make it end early, and maybe automatically pick up any remaining gold and end it if you kill the boss. And make a way to move around in the upgrade tree instead of just zoom out. Or did I miss that?
You can move with middle mouse button, but I guess it's not intuitive and doesn't translate well in the browser version. I was thinking about moving it on LMB (especially now that there is multiple people telling this :D)
Yes, I'll do a better balance pass for next update.
Thank you for posting feedback <3