I cleared 10 waves the most.
I got careful of never ever choosing faster enemy bullets, this seems like the real trap. During this one run where I got the furthest I got tons of hearts (got something like 8 in the end?), although I really like that there are different possible approaches as for example if you choose multiple Time bursts you'll obviously also choose the upgrades which give better Time bursts, which is also my favourite way of playing.
I love the game. It looks and sounds pretty good, controls perfectly, is somewhat unique (ironically the one thing some other people did a similar way is the theme implementation ;) ) and the main mechanics work super well, there're really super pleasant to control, and allow for a game where there're constantly tons of bullets on the screen which is why we're here. There're not tons of different enemies but the ones which are there are cool with interesting different patterns to deal with. The speed of the character and bullets is perfect and the game just as hard from the very beginning which I really like, I tend to much prefer that to progressive difficulty maybe in general but specially in games you'll get to replay from the start several times, here it's satisfying to beat each wave.
There's one thing I don't understand, and now while typing I even wonder if it's a bug : at the beginning of a game I need to press the button to use the bullet time in order to damage enemies (I need to be in bullet time mode) but consistently from a point I only need to touch them (I don't need to be in bullet time mode anymore) for the remaining duration of the run. It does not even matter that much while playing but it's confusing me.
Very cool game, thanks for sharing. Is it endless by the way? If it's not I might try to complete it.