Art is nice and I like the music. The gameplay is addictive and there's a nice bit of challenge to it. I like the idea of waves being determined by a timer because with many games like this (where you restart after death) starting from wave 1 and moving to wave 2 can be very tedious and a time removes that in my eyes. There's a nice bit of challenge going from wave to wave and making progress is satisfying. The final wave lives up to a bullet hell theme. I also liked the variety of enemies in the game with their different bullet patterns.
Some critiques I have is I wished in the scrap yard I could see how much an upgrade is worth, so that I could strategize on saving or spending scrap. As well having a short description of what each upgrade does. While the timer is nice for keeping the game going and not spending too much time in a wave it would be nice to have a way to progress to the next wave if you complete it early (The game is called 10 second arena so doing that would be going against its name). I will say the game does get a bit easy when you unlock the shotgun and the radial gun. Especially the radial gun, because at that point all you need to do is click fast and dodge the few bullets that enemies are able to fire off. I unlocked the dash, but I never really used it much since you had to use the shift key and it was a little awkward to reach with my finger. The few times I did use the dash I didn't find it very helpful.
Overall I was satisfied with this experience, and I see a lot of potential for this game. I hope the developers continue to do more.