Minetest is a sandbox building game, inspired somewhat by Infiniminer but mostly by Minecraft, created by Perttu “celeron55” Ahola. The game play is very similar to Minecraft’s, consisting of creating and destroying blocks in a local or online 3D environment. It is Free and Open Source Software, released under the LGPL. It was done this way to be more readily available to Linux users, and so that random people in the open source community could fix bugs and experiment effectively.
And for the people who say Minetest is a ripoff of Minecraft, then Minecraft is a ripoff of Infiniminer, Buildville is a ripoff of Minecraft, Terraria is a ripoff of Minecraft (Terraria is also partially inspired by Minecraft), Starbound is a ripoff of Terraria so it’s also a ripoff of Minecraft. And if Minecraft is a ripoff of Infiniminer then all of these are a ripoff of Infiniminer. Voxel/Block based building games are NOT always a ripoff of Minecraft, for more information visit the Minetest Information page containing many links to more documentation.
1.) Update System.
It is always best to make sure that your system is up to date. Open the Terminal (CTRL+ALT+t) and enter this command to chec for and install any updates that may be available.
$ sudo apt-get update && sudo apt-get upgrade