So minetest? minetest was created by a guy named celeron55. The origins and name lead me to assume this started out as a college project that gained traction faster than a good name could be chosen. Either way its certainly the most well-known open-source voxel game engine / game and second to that is another project known as Terasology. The main problem in my opinion with both of these projects is a distinct lack of a playable game. Minetest has terrible default graphics that rival my pixel creations 10 years ago and Terasology is an amalgamation of random Google's Summer of Code projects and a serious lack of online servers.

Then sometime later this guy named daredevils started working on a project Mineclone, it was simply a collection of mods for minetest designed to imitate Minecraft. And although the information here is a bit fuzzy, it is clear that he eventually gave up on the project. Wuzzy, a popular contributor to minetest mods, decided he would reboot the effort by starting a project called MineClone2. Since then the number of minetest servers running mineclone2 have been growing and, arguably, the project is the most active "game" for minetest.

MineClone2 although permanantly in an alpha state has been making great strides to keep up with Minecraft. In fact just recently a large modification was made to add potions and brewing to the game. There are some discernible differences certainly in completeness because things like villages are not stable enough to be implemented yet. But, its really easy to get started with this project. I myself have made a few significant contributions to this project. Notably, I wrote the code to make enderman behave more like the enderman from Minecraft. I also added an initial implementation of fishing in the game although due to engine limitations you still can't see a visible line. The reason it's so easy to get started with this project is because all the code is written in Lua which is comparable to Python. To top it all off, after every change you don't have to recompile all the code, which is really great for quickly making changes to see what happens.

Setting up a server isn't terribly complicated and to simply play the game all you need to do is download minetest and connect to a MineClone2 server. The client will fetch the necessary assets and its a great way to test out the game. So, even if you have tried minetest and been disappointed I really recommend you try MineClone2, even the graphics are better. Seriously, don't take my word for it, try it yourself!

You can download minetest here: https://www.minetest.net/downloads/
You can download MineClone2 here: https://forum.minetest.net/viewtopic.php?t=16407

Note: As of writing the website for downloading MineClone2 is down, but I expect it to be back up soon.