Clonk! It’s a 2D mining/strategy/base-building hybrid that was apparently more popular in Germany than other places. I actually paid to play it way back in '05, but it has since become freeware. It’s got a particle sim (similar to Noita, but not as extensive) that plays into the scenarios well.
One of my absolute favorites is a quirky strategy game named Lord Monarch. I found it on the Nihon Falcom website way back in the mid 90s when I was first starting to use the internet: Lord Monarch
It’s super tiny in modern terms, but I remember waiting a good 20-30 minutes for it to download from a 33.6Kbps modem.
Another huge one for me was a game I actually got a full version of from a Gravis gamepad promo CD named Seek and Destroy. It’s a top down shooter where you can be either a helicopter or a tank: Seek and Destroy
The last one that comes to mind is a giant robot fighting game that also came on that same Gravis CD named One Must Fall: One Must Fall 2097
UnReal World is a free, survival-focused roguelike rpg that came out in 1992 and is still actively being developed and improved. It’s got a lot of depth and a very cool fantasy setting heavily inspired by Finnish folklore (the developer is Finnish).
I highly recommend it if you’ve got the patience for an in-depth roguelike rpg.
For the longest time I thought Minecraft was free because I only ever pirated it. Lol
PlanetSide 2 is the free-to-play I keep going back to
Heck, I still pirate it even though I bought it. (I didn’t want the hassle of migrating my account after the Microsoft buyout.) PollyMC ftw!
Irisu Syndrome! is a favorite of mine. It’s only from 2008, so I personally don’t consider it retro. It’s tricky to learn at first since it doesn’t tell you anything about how to play and I don’t recall there being a manual. It’s also one of those games that you can’t really say too much about without spoiling things.
Wolfenstein Enemy Territory, or the modernized remake, ET Legacy
Haven’t played recently, but this one came to mind’
I missed the original, but Scorched 3D was a big hit at my high school.
Squarez Deluxe
Makes Tetris seem like a children’s toy
If we’re sticking strictly to free, I’m not sure Doom mods work if you only have the free version installed. Either way, people basically never stopped making wads since the game came out, and I try various ones out from time to time.
There are tons of them, so if you’re interested you can see what won the annual Cacowards throughout the years and start there.
Super Crate Box. An incredibly addictive, simple 2D shooting game! It’s free on Steam!
“Einstein puzzle” by Flowix games, copyright 2004-2005
I play it from time to time, to see if I can still complete it in under 4 minutes and my brain isn’t slowing down too much with age.
Technically, Dwarf fortress is the oldest game I still play, but I only got fully into it thanks to the non-free Steam version.
Tyrian is still fantastic 30 years later!
Love this game!
I’ve probably played this game for over a hundred hours. Great soundtrack too, by Alexander Brandon. I also loved the minigame hidden behind the DESTRUCT cheat code.
And it’s open source too!
Beneath A Steel Sky (though I kinda prefer the grungier aesthetic of the Amiga floppy version)
Available free on ScummVM!
Has an excellent plot and wry sense of humour. Fun game.
Frog Fractions
I don’t play it regularly, but it’s fun to tell people about it.
I don’t know if it technically counts as freeware, but Space Cadet Pinball. Back on XP it was my go-to for something quick to play on the offline computer, and I just brought it with me to every new machine. Also it’s now been decompiled and will run on pretty much anything!
