https://evens.itch.io/space-fleet-amber
Space Fleet Amber is a pixel art R-Type-like memorization shooter with some randomization on a per run basis.
Blast through 20 minutes of shooting action then come back later and get an experience just that little bit different with different weapons, enemies and ships and a selection of interesting secrets including multiple secret bosses to find and beat.
This originated as one of those forever games that I was tinkering at in Gamemaker Studio in my off-time to try and push my pixel art skills. I wasn't expecting to ever get it done but now it's just about finished (I think) after seven years of occasional work.