Hidden and Dangerous

Only H&D2 is on steam

The original was fantastic and v2 built on that. Fantastic 3rd person WW2 tactical shooter. Haven't seen anything like it in over 20 years since.

Children of a Dead Earth is a tactical space game with n-body Newtonian physics. This means that on the surface it is very similar to something like KSP, you can do things like orbit a Lagrange point. In addition, you can design all the parts of you spacecraft and weaponry down to the materials they use. If you can make a fuel tank made out of aerogel work with the laws of physics, then you can use it. For example, I made a coilgun that fires nukes which was devastating at close range but the low velocity of the nukes made them easy to dodge at long range and without any thrusters, they cannot course correct.

Taipan!

A naval trade game about 1800's China from the Apple II. You won't believe it till it happens but I'll become addicted.

Clanfolk, a (very alpha and also very playable) game that draws clear inspiration from Rimworld, but has a kind of tech progression that feels spiritually similar to bootstrapping a factory in Factorio, while being set in the Scottish Highlands.

Out of Space a cozy co-op game similar to Overcooked but less chaotic.

Eternum (warning: NSFW) is an adult visual novel that keeps touching me with every new update. It's completely free, and I can't help but think of the creator as a master of the genre.

The characters are all well written and (those who are meant to be) lovable. The story is interesting, compelling even, and the humor is often hilarious. When you go to the website, you might think "Porn game!!!", and not be entirely wrong, but Eternum is so much more. It's a story about love, friendship, and a mystery.

Setting: Orion moves back to the USA after a long time. In recent years, a video game called eternum has been gaining traction, that allows going into virtual worlds, think full dive VR like in Sword Art Online. I'd say about 60% of the story happens IRL.

I can only recommend this masterpiece of a visual novel.