I've been following the dev updates you posted on the GWJ discord! Knew this was going to be special when you found the CRT shader. Really nailed the retro feel of the game + the grided wildcard. The music matched perfectly as well. I went straight for the Hard mode and got destoryed by my poor aim. Amazed that you managed to add in upgrades as well in such a short time.
A lot of nice minute details too, such as the arc of the arty shots, and the visual cue text on the state of the artillery. One of the most polished games I've played so far. Can see people playing this on the go it there is a way to accomodate the controls for touch.