It ran smoothly on my Steam Deck
If you will run default "Minetest Game" or other simple games on Minetest - it will be almost fine, but that will not work for any complex game.
First of all rendering system of MT Engine is very bad:
- It separates each texture as individual submesh in the chunk instead of using texture atlases or texture arrays. That means that each chunk will require from 1 to several hundreds of drawcalls (people who know rendering will quickly understand what that will mean for performance). In comparison MC uses 1-2 drawcalls per chunk (if there are transparent blocks or not). That means that same amount of chunks on the screen will require up to 10-20k of draw calls (if there are many textures). Each draw call require CPU-GPU data sending, which is the bottleneck.
- All animations are done with mesh UV switching, any animated texture will require recalculation of thousands vertices in each chunk where it exists, and sending result to the GPU. And that will happen on each animation frame. In comparison MC just changes pixels of the texture. Sending 256 ints is much faster than some hundred thousands of floats to the GPU
- Light system uses several storages - artificial light, sun light and moon light. Some devs don't even know how it works, but in general it will require much more complicated and massive calculations. And it will require rebuild meshes on day/night cycle changes. In comparison - MC uses lightmaps and have only 2 light types - from blocks and from sky.
- Entities code is very inefficient. Default game (and most others) don't have any entities except player and items. There are many weak points - finding other entities will ask all entities in the world instead of neighbour regions (same for physics), and so on. If you have more than 20 entities on the screen - you will get lag
- Server code is also inefficient, servers with more than 3 players and with complex game than default will have lag (freezing animations, rollbacks, physics glitches. Your FPS will be stable, but gameplay - not)
Physics is also not very good - it works more like physics in liquid than in air. Acceleration for entities and player is frequently incorrect, when player don't hit the node the engine will slowly push player down during a second, entities inside nodes starts glitching (especially items). The last one was partially fixed from LUA side in default game.
Basically MT engine is worse than MC engine during beta period (which was in 2010-2011). Even Modern MC with its runtime object creation and other specific things runs much faster with much more complex calculations than MT by default. RW engine (Unity) is also nice in terms of performance (that's also related to RW dev team code optimizations too)
Maybe the developer is corrupt, maybe not. I have yet to find that out. What matters is how well it runs on a very basic level while adding the very basic core fun and entertainment to the table.
Minetest is not a game anymore (since 0.4.0), it is a game engine now. Since 5.8.0 default MInetest game was finally dropped from default installation, now user should select game manually. All features that devs will add are code/API only, all games for the engine are developed by the community. The problem is that devs of the engine don't actually implement what community ask, in most cases they have their own vision of how it should work. For example they dropped all renderers support except OpenGL, even if they don't need to maintain them since they are using Irrlicht as rendering engine (for some reason they made their own fork and remove all rendering code except OpenGL. That can be understand if they will update its OpenGL version or at least enhance engine to support texture arrays, vertex attributes and so on, but they are not doing this). As a result Minetest Raytracing is no longer possible, instead we will have effects like in 2010 games like bloom that looks like vaseline on screen and very questionable godrays. Some PRs made by the community can stay open for years without review (even if they are important), others can be closed due to different random reasons
Microsoft is ruining everything they touch
Like any capitalist Microsoft is earning money, and looks like they are good at that. Actually without Microsoft MC will probably just become stagnating in 2012-2014 and slowly die (that was an update crysis when MC hit the bottom of its popularity since 2011). Yes, the game lost most of its original identity, but it also get many new things to work with. Yes, we don't have simplified villagers that can only walk and open a randomized trade menu, now we have complete village mechanics with jobs, necessary beds and houses, complex trading, village sieges, wandering traders and so on. We don't have only one world to work with two additional barren places, now we have 3 complete dimensions with their own resources, benefits and experiences. We don't have programmers art textures anymore (well, you still can enable them), instead we have a complex set of textures that are connected with each other, when you can finally build not only from stone and netherrack bricks. We also get many other things that were originally promised by Noth, but not implemented at all - cave biomes, ocean content, advanced End boss fight, complex customizable worldgen, advanced rendering system, multithreading and many others. And Mojang finally clarified their EULA (which was not clear since 2013), now all rules about user-made content are finally clear.
Additionally Microsoft expanded Minecraft universe, now we have Minecraft Story Mode, Minecraft Dungeons, Minecraft Earth, Minecraft Legends. Yes, not all these games are good, but without Microsoft Mojang will never experiment with creation of something except Minecraft. Minecraft Dungeons actually looks like a Minecraft that we all want to see - with nice graphics, animations, textures, models, story and combat. It also has much better environment than original game. Without Microsoft that will be just impossible