Take on Mars is more simulation than game, and clearly showing that the goal was a simulation first, and a game second. That said, it remains very interesting and works quite well as a game, when you can figure out how to do things and get it to work.
And that is one of the problems. The biggest problem however is the complete lack of time acceleration and slow speeds. I understand wanting realistic speeds in your simulation game, but this is not an experience that any but the most patient people are willing to go through. For reference, to complete the unmanned campaign you will need to travel ~50,000m at speeds between 1.5m/s and 2m/s, or in more understandable terms, your rovers go at the speed of an old man with a walking aid and you need to travel roughly a small country's length. The game does helpfully offer you a realistic wheel speeds option, which will bring your speed down to around 0.6m/s, or roughly the speed of that old man if he had to stop to take a breather after every step. I firmly believe that I am one of the most patient people in the world and submit this game as proof for that.
With the biggest problem out of the way, the smaller problems are still noticable. It essentially does not tell you how to do or use most things. When starting a campaign, the first thing I had to do was push every button on my keyboard in the hopes that it would move along the interactive first landing of an historical Russian lander. It worked eventually, and I could play the game after that. After that, you are never told how to use specific instruments, and you aren't told what technologies actually do for you as a player. But that is something you can figure out as well with a lot of looking for things, so eventually it will work out.
There also still appear to be a fair amount of bugs in the game, including random missions asking you to take microscope pictures of the atmosphere, and one that makes it so missions do not spawn when they should so the game literally becomes unfinishable. With the last one in mind, I had to stop my playthrough before I could get to the manned stage, as the missions I needed to complete did not ever show up. The physics at times become a large problem in that your science instruments need to be held still to do science, but the physics tries to make your rovers almost dance, which makes it nearly impossible to use your instruments unless you forcibly jam them against the rock or sand you are trying to perform experiments on.
Even then, Mars is a nice and often varied place, with a lot of interesting terrain and good looking locations, with missions placed so that they show you to all the good places with almost scenic tours. The economic part of the game- Getting your funding, is very rough early on and practically doesn't exist in the later stages. This may be to save up money for the manned missions, but I never actually reached that part, so I wouldn't know.
All things said, Take on Mars needs work. It is not an unpleasant experience for one with a lot of patience, but I struggle to see what would draw in anyone other than the most scientific minded people who at the same time don't mind gameplay. For anyone else, it is a nice novelty, but very repetitive and slow. There does not seem to be that much here, at least not in the unmanned campaign.
There is also a multiplayer mode, but I've yet to be able to motivate anyone into playing it with me. I will update this review whenever I get people into a server with it.