Stellar Interface [Steam, itch.io] is a rather crazy looking space shooter with a randomly-generated galaxy, it recently gained an Endless Mode too. This is one from my list of "games that got buried", it was previously in Early Access and it's been updated rather a lot.
I'm a little unclear on when it released exactly, as they put November 21st 2017 on Steam, but I can't find an actual "release" announcement for when it actually left Early Access. They had a "220.127.116.11" release on November 21st 2016 and they announced an "Anniversary Update" on November 21st 2017. I'm going to assume the actual date on Steam has the year wrong…
Anyway, take a look at the trailer for the new mode:
It looks absolutely nuts, love it! Visually and in terms of the action, it actually reminds me of Zero Wing from the Sega Meagdrive that I put endless hours into when I was younger.
About the game:
Run through the universe, discover the numerous perks/consumables and their synergistic effects. Explore the randomly-generated galaxy to find merchants, unlock spacecrafts, collect StellarNetES Cartridges, checkmark your kills of the various galactic overlords.
And die. A lot!
Can you find the most outrageous perk combination to defeat the Last Overlord?