Yes, that trash is what I meant when commenting on the Windows build! I'm not seeing it in the Godot web build.
By sub-pixel I basically mean that since monitor pixels are smaller than "game pixels", we have the option of upscaling sprites individually instead of upscaling the whole scene (see here for examples: https://medium.com/@tumeowilliam/godot-engine-and-pixel-art-a-better-love-story-...). And this could help with getting smoother movement (this is not pixel-perfect, but during movement it's not obvious).