Absolutely no recommendation as a game. This is just too boring even as a tamagotchi. It is probably WIP/incomplete anyway. At this stage, it might serve as a screensaver at best.
This is a very early prototype, so there is very little of what you could call "gameplay". You mostly just watch forms slide around on an orange asteroid, that's it. You can raise the ground at certain places and add new space worms with a maximum of 3. That's it. You can't even undo the raising of land, that's how incomplete this is. It gets boring instantly, sorry. First, this is not a game, as there is no gameplay. It is more like a tamagotchi. That alone isn't a problem, but even as a tamagotchi is has nothing to offer since you just can't do anything. And if all you can do with the worms is just watch, you can hardly call it a game.
It's still interesting to see new concepts being tried out in Minetest. I believe something like Adopt a Space Worm! was never even tried before, so I give a few points for the idea. :P
Very minimal. The worms look kinda cute, but not very detailed. I observed only two behaviors: Sliding around, and sleeping. The worms don't interact with each other. The asteroid is a flat orange which is ... meh. There is a very blurry space background. The menu interface doesn't look too great either.
Stability / Performance
It doesn't crash, but: The game greets me with a "missing image" error. Space worms can get stuck if you raise the ground into them. There are no performance problems at all. At least the worms seem to be intelligent enough to avoid the void or walls, so the very minimal basics seem to work. That's better than nothing, I guess.
Music / Sounds
It is silent except for a few click sounds. :-(
It's not self-explanatory, and the buttons look like they are written in an alien language. But I still was able to figure out what it all means, so the UX is fine.