Love the visuals, as I've mentioned before. Will definitely be coming back to this one for future co-op. Also, rad screen effect to and from title screen.
It could benefit from an additional mechanic or two though. Personally, I'd suggest:
- Something for a quick boost of speed (maybe once per wave or earned in another way); and
- Some type of collectible wave between enemy waves for some risk/reward (keep my ship close to guard the tanks or go get the coins/whatever).
You could even kill two birds with one stone and have items that spawn between waves to regenerate the boost.
Oh, and the only reason I knew there was a 2-player mode was from previous discord conversations. Combined with the fact that streamers seem to read Tarmac, the default stage setting, as part of the title/introduction text, restructuring to a more traditional title screen (1P/2P start followed by stage select) might help.
All that said, what's there is really well executed.