Fair points but look at the sword on your opening screen and the tiniest particles as they disappear, they're made from many more pixels then one of the 'blocks' making up the left-hand wall (which represent units in your 64x64 grid). I think a lot of submissions have suffered from the same problem: the rendering seems to be beyond the programmer's control. Modern game engines sometimes make things harder than they should be, usually, and ironically, when aiming for simplicity. It's one of the reasons I've eschewed them and gone back to making simple pixel games with no cameras, canvases, shaders or lighting...beyond what I can create myself from raw pixels.
Anyway, back to your game, which I skipped over in view of the foregoing. How do I swing the sword? I'm suffering a rapid demise which prevents me from exploring further!
P.S. In your write up you mention Aseprite but there's a free fork of this, LibreSprite, at https://libresprite.github.io/#!/ which is rather excellent.