This is an experimental(!) Engine for multiplayer games, which runs on FULL synchronization of games, has very large limitations for games (this engine allows you to create very complex in-game mechanisms, such as piston structures, as in Minecraft, working Right in the scratch! (without turbowarp/forkphorus, but this requires strong optimization because the same ticks can be calculated 10 or even more times in 1 frame)). This engine is not tied to FPS, which is why it will run at the same speed, even if you turn on turbo mode (or vice versa, FPS will be less than required, which will cause it to "catch up" with the project, which can lead to project freezes, so be very careful!).
I am currently developing this project and it seems that synchronization is successful when a new player is connected. In scratch, this project will slow down a bit (if you connect a second player or more, the lags will increase, but it will still work normally, I will try to optimize it as soon as possible). You may also notice that each client does not transmit a specific location (only at the beginning), but its movement, which allows you to fully synchronize projects, even if there are mobs/pressure plate mechanisms/ other players in the project that you will encounter (this is not necessary). You can also add your own actions (add the ability to arrange blocks, chat, interact with the map (chests, inscriptions on chests/tablets, etc.), NPCs, etc. The ability to add up to ~1000000000 types of items, about the same number of data digits for these blocks, about the same for entity. However, do not forget that the more you save memory, the faster the dump will load (dump is a dump of the entire map, all entities, etc.).