This is probably the most realistic Mars game I have found.

Horrivel

This game is either for you or it is not. There is no in-between. It is slow, there are no aliens or bad guys or guns, it is all about surviving in the truest sense of the word. If you want a slow-paced relaxing game where nothing happens but maintaining your base and feeding yourself, this is it.

I've played this game several times, despite the sad fact that it's incomplete. You get six missions, and then you're just kind of hanging around with very little to do, except harvest more plants and dig for more ore. The developer has supposedly been ill for the past few years, but recently announced that he's working on these games again, so hopefully there will soon be updates.

As far as the game goes, right now, the graphics are a bit crude, but I like them. More to the point, this is hands down the best Mars colony sim I've come across. The game understands that Mars is largely silent and cold, and the dust storms aren't going to fling anybody across the landscape. The biggest issues are power, heat, air, and food, and you have to assemble your base to provide these. In the meantime, equipment breaks down and needs to be repaired. The feel of Mars Colony is probably similar to the feel of living alone in the Antarctic... but with fewer penguins.

Other Martian sims are admittedly more exciting and have better graphics, but none of them are as accurate. It feels REAL. And that's why I've played it more times than I recall.

I did play it much more before Steam release, in old Mars Alpha Base and by playtesting.

There's quite deep simulation of martian base with atmosphere and energy control systems.

Production chain Water ice -> Oxygen-Hydrogen+CarbonDioxide = Methane
Also food growing-breeding (vegs, fish, algae, shrooms, worms) and waste treatment.

But my favourite part is mineral prospecting and mining.
You need to collect and analyse soil samples for contained minerals and find biggest concentration.
Then check that location from several points by Ground Penetrating Radar scanning to get coordinates of ore vein under ground. Triangulation!
Then you can drill it deep by small rig to find actual mineral in that vein.
Then you can bring and disembark big mining rig onto that spot to extract the ore after long drilling to depths, which need to be processed into needful elements for manufacturing into spare parts, medicine or fertilisers.

Also there's some weather, cold radiation storms and need for pee.

But quite gloomy gameplay without any music or dynamic (recommend the disco soundtrack).
It much more interesting to play in multiplayer cooperative, trying to reach biggest point of colony work effectivity with specialisation of coworkers.

Nice ideas but this game feels like an Alpha release. Sound effects are missing. Graphics are too basic. User interface needs to be more user friendly. Game is meant to be played with others. Game even crashed on me. :-( Gave up and moved on.

Unfortunately I can't recommend this one. I bought it back in Early Access and thought it had potential, but unfortunately it remains incomplete. The UI is obtuse and quite annoying. The jump between phases left me feeling like I was missing out on other parts that could have been included. There are little things missing all the way through which makes playing it a chore.

Unfortunately this is one is a no from me.

great game, such a classic game to play while waiting for a better game to install!

Short, but I enjoyed it.

THis game does not Offer What you think. It has low Res. It doesnt have very good building mechanics. Enviromental Controls are WAY off too. I cant see something that wont go wrong in the Game. Also it's pretty buggy.
Thank you for Reading,
-Mr. Kaos