I know this might be an unusual post, since this is a new game, but hear me out!
I just picked up UFO 50 this week, and I can't recommend this enough to anyone who loves retro gaming. The premise is that this is a collection of 50 games from a fictional 8-bit console in the 1980s, with a little info card for each one providing its release date, developers, and some trivia. The game selection screen shows 50 cartridges to choose from:
These are all full games like you might have seen during the era - not minigames or demos, and the ones I've booted up feel pretty authentically 8-bit (with some modern QoL things thrown in). There are all sorts of cool ideas and game types: platformers, a point and click adventure, bullet hells, at least one full JRPG, etc.
Some examples:
It looks like as you browse through the chronological library, you see a sequel or two of previous titles. This was made by the team that created Spelunky, and it wasn't even on my radar until I fortunately saw a video a few days ago of one of the individual games (followed by some confusion when I couldn't figure out where to buy that game by itself). If any of this appeals to you at all, I highly recommend checking it out.
I've barely dipped my toes into the games so far because I keep coming back to Ninpek and (I forget the name) the one where you keep jumping upward and try not to fall.