The quality of this game is through the roof, especially considering it was made in only 15 days! The only complaints I have are all so minor they didn't really affect my experience that much:
- There didn't seem to be any difference between the enemies. Not that it was a problem. The skill tree had all my attention absorbed, so I wasn't really thinking about it.
- Perhaps a slightly faster way to collect coins in the larger combat rooms? Or maybe I'm just too trigger-happy.
- In the larger combat rooms, occasionally enemy billboards would z-fight with each other.
- Invincibility felt more like health. And while everything was polished and balanced to the T, none of the mechanics particularly stood out as revolutionary. At the same time, "Invincible" is a difficult theme to deal with.
- While I could definitely see how some would enjoy searching for the corridor coins, it slowed down gameplay, which made it a bit fatiguing for me in particular. At first, I felt obliged to collect them all to optimize efficiency, but after a while, I ignored them so I could go through the runs faster. In contrast, I loved the weakness exploit ability. It added a thrill to combat.
- Eventually I got to the point where I could one-shot most enemies, so I didn't feel any need to upgrade my sword, which led me to ignoring crystals all together. Instead, I would try to upgrade chain lightning so I could take out multiple enemies with one hit.
I'm only writing the negative things, because if I wrote down the positive things, this comment would be way too long.
Excellent game! (and I'm not just saying that :D)