Simple, and fun enough to where I went overboard. I went for 10m glory and it went in to notation haha. Took about 2 hours.
Maybe you could add a status window to the pause screen so that you can see how many upgrades you've unlocked and the value of each stat?
The only criticism I have is boots need to be either capped or the growth of speed needs to be lower. After about 6-7 upgrades I felt like I was about to lose control of the character because it was too fast.
Whoa, If this doesn't count as winning the game, I don't know what does. Since the skeletons don't scale infinitely, I knew eventually somebody would out-scale them. I already nerfed boots once, guess they're still too strong - If I make more patches to the game, I'll make every boots upgrade weaker than the previous one.