SuperTux is a typical 2D platform game which is very similar to the popular Super Mario Brother series from Nintendo. You play Tux, the Linux mascot, instead of Mario and you're trying to rescue Penny, not a princess. Oh, and you're in Antarctica. That's about it when it comes to major differences between SuperTux and Super Mario.
Graphics and gameplay
The graphics is fine, it is actually quite good for a game like this. It's not all that impressive compared to modern 3D fps games but it's good for a 2D sidescroller game.
Gameplay's what you would expect for a Super Mario clone. There's blocks you can destroy and sometimes there's hidden items in them. Some boxes are marked with question-marks and items appear when you bounce on these blocks. There's coins to collect and power-ups to be had. It's basically Super Mario in a slightly different setting.
It's quite fun if you like 2D platform games.
Anything capable of rendering OpenGL graphics will run SuperTux just fine. It's playable on a Raspberry Pi.
Verdict and conclusion
It's a fine free game and the latest version, 0.60 released late 2018, is available in all the Linux distributions repositories. It is definitively worth installing. It isn't fantastic compared to many of the modern games you can get from Steam but it's open source and free. It is quite good for what it is: A Super Mario clone with more updated modern graphics.
There is active development but there really isn't that much new since the 0.6.0 release so the distribution's version will be fine, there's no need to download and compile the source.