Much like with Box World 3D, I don't really feel the need to describe the game because I suspect everyone here has seen a maze before. And indeed, this game provides mazes just as promised!
The game has some nice touches, such as providing a soundtrack (with per-theme tracks even!) and some custom UI for picking mazes/restarting if you get stuck. I didn't see any bugs while playing, and what's there is relatively well-polished. Some of the themes also have neat visual touches, like the fake reflections and particles of the club theme or the fact that the glass theme is a hell that will haunt my nightmares tonight :)
If there's one clear improvement I'd like to see eventually, it'd be a proper 3rd-person mode where you look down at the maze. Switching camera modes kinda works, but it's a very janky and disorienting experience due to the camera clipping and lack of player model. Having a more polished custom solution would be really neat, and I think it would help add more replay value to this otherwise short experience.
This is not a game I expect anyone to sink hours into, but it's a nice way to spend 15min and it speaks to the presentation possible in more restrictive Minetest experiences. Good job.
Proper 3rd person mode is not something I had considered, mostly because it feels like cheating to be able to look over walls in certain modes, though I can definitely look into it. Since this is a single player game, it should be quite easy to override look direction and position with a global-step, so we'll see if I can get the time to implement it :)
As for the UI, haha yeah it's mediocre, but I'm curious how you would improve it? Feel free to provide a paint.exe or equivalent mock-up, I'm open to ideas there.
Alright, here you go: https://www.youtube.com/watch?v=NkGqt52QBqE. Instead of a mockup, I figured I'd just do something to the game's formspecs instead. It's not perfect, but I think it offers one possibility! You've got plenty of other options depending on what you want to do with the game.
The general layout and white background got me thinking a bit of material design, so I played around a bit with buttons, colors, layout, etc. to try and hit that general aesthetic. The goal here was to keep the same approach/functionality.
IMO you could also do something like adding a play button, treating the existing buttons as a grouped toggle buttons, and disabling (and reducing alpha for good measure) the text fields when 'custom' isn't selected. This would increase the number of clicks, but might make things clearer? It's a matter of opinion, and I didn't want to go to the lengths needed to code in something that arguable. Oh, and I also didn't touch the in-maze menu... I got lazy.
I can't share the code/textures involved for some personal legal reasons, but I'm aware that formspecs can be a huge pain to work with and I'd be happy to answer questions about how I did this if you have any.