I think this is a neat prototype, it has that Metroidy feel to it while having its own uniquely punchy visual and audio style. I didn't get too far in the game but I just wanted to leave a couple of points of feedback based on what I experienced:
1. The dash seems to go straight through any sort of environmental boundaries- it's very easy to phase out of the edges of the map accidentally, especially if you dash diagonally. While this is very funny to do there's a lot of instant deaths that can happen this way.
2. It feels very weird and inconvenient having to use the mouse to fire, especially when you can't actually control where you aim with it. I'd prefer just having another button on the keyboard like K or L or something. Also, I don't think Ctrl should be used at all for a web-based client game because depending on your browser or specific operating system these can very easily accidentally trigger a lot of random gameplay disrupting shortcuts (like if you press ctrl while moving right this triggers the "create bookmark" shortcut in Chrome which pops up every single time this happens).