its a great game, but has a few flaws
graphical flaws=when you keep on hitting him in first form and his does the whole red pillar of doom thing, it cuts out just below him, which you can see if you jump on a platform
gameplay/balance flaws=on the first sword upgrades (darkgene + the other one) when you pick up amethyst, its a adamantite and vice versa, but this disappears once you upgrade again
if you hit the thief multiple times, you can only pick up the first stone he dropped, then the second and third, or wait until the others have disappeared in order to pick up the one you want
you say you upgraded the drop rate for the last two gems, but even so it still takes 10 minutes of chasing the thief round just to upgrade the sword a second time?
one more balancing issue, if you go pure agility, even after 14 minutes of chasing the thief round, you might have lost a life but still have half a health bar, as a 50%+ dodge ratio is quite high, maybe one point dodge ratio to one point in agility?
despite all these its still a great game, though it detracts from the quality a bit