If I'm playing a frustrate-y, challenge-y kinda game, one of the absolute MUSTS for me is a seamless and painless reset, and you did a great job with that here, and the design choices to keep things like the bgm consistent/uninterrupted on death, there aren't big video or audio signals, and that all kept my head level enough to just keep at it for quite a while. Nice mechanic, with the arena growing, too. Simple, but not plain simple - elegant simple.