Retro/Grade is a rhythm/shooter mashup where you travel backwards through time and un-fire a bunch of lasers to un-kill a bunch of ships. It was designed for a guitar hero controller if I recall? I found the visuals nauseating and the music lackluster but that premise is gold and deserves another chance.

Also PLEASE play the music backwards??? It's a game about going back in time, c'monnnnn.

Marble Blast!!

It was one of the first PC games I played as a kid. Incredibly simple mechanics: you are a marble and you roll and try to reach the finish line (sometimes you need collectibles first). But the level design was top notch. Perfect blend of challenging and rewarding.

I'd love a new, bigger Darwinia game, loved that back in the day.

Plants vs. Zombies: Garden Warfare

It's a shame that it doesn't seem to have that many players anymore. It's a lot like other multi-class shooter games like Overwatch and Paladins, but about three times more crazy and weird, and I had a ton of fun playing it as a teen.

I've heard Garden Warfare 2 is pretty good too though, so I'll consider buying it at some point (when I have money).

Burning Rangers from sonic team on the Sega Saturn. Such a unique concept.

Rock Manager. It was very limited in scope and quite short, but it was a really fun game with tons of potential.

I've been unsuccessfully looking for games like it that are as good as it could have been or even as good as it was for over 20 years now.

Pax Imperia: Eminent Domain. Quite a learning curve, but I loved the different ways you can win (conquest, trade, black ops) and how much you could customize your ships or pick unique races with tolerances for different planets.

Blinx the time swipper, haven't seen any other game trying to play with time like that.

Oh, and crimson skies.

Elebits! The sequel plays nothing like the original and I would love to have it get a proper sequel! The art and character designs were done by Akihito Tsukushi, who created Made in Abyss, another great thing I love very much!

Test Drive Eve of Destruction from the original Xbox and PS2. More recently, Code masters' OnRush.

Dark Savior. I don't think I have ever seen anyone mention this game ever (without googling for it).

Circuit's Edge and Ranger X !

Anachronox. Ion Storm at it's best. Engaging plot and characters, humor well ahead of its time for a game script, and party members and environments that I've still never seen many games match to this day. I don't know why it didn't become huge, I think the rpg crowd back then was still pretty married to sword and sandal conventions. If you like old games, I can't recommend it enough.

Valve's Artifact Classic card game. I actually found the basic formula to be really fun.

I think this game died for two reasons:

A) The game was review bombed for its monetization (IMO a lot of this was the non-target audience trying it and leaving a bad review)

B) Valve said following the review bombing that they were going to make major changes. This resulted in a lot of Artifact fans (IMO) leaving the game because ... why invested and learn a game that's going to undergo major changes.

So Valve worked on Artifact Foundry (and never finished it) ... before eventually everyone at Valve gave up and released both Artifact Classic and Artifact Foundry for free. The original Artifact Classic is still a great time with a friend and all cards are now totally free so you can build whatever decks you want.

It's basically a AAA studio card game, with cross platform support, released in complete, for free ... because of some poor decision making. Some things may be unbalanced but if you're playing with friends anyways ... just have a friendly agreement to not use the cards that cause problems in your decks. It also could bounce back into active development if it starts to acquire a player base again (because Valve).

Sacrifice

Sacrifice. I am so sad it didn't have a bigger impact than it did. What an amazing game.

I'll throw out one from my youth that I think would be really good to see updated:
Sentinel Worlds I: Future Magic. It was a very early space RPG which was way ahead of it's time. Something like the recent Heat Signature kinda reminds me of it, though it lacks the scope and depth of combat.

Dragon Valor for Psx.