LÖVE

I want to create a game, in wich you can controll vihicles with a script, wich can be written by the player.
It should be run in a kind of sandbox, so the player cant controll the server wich bould make cheating dead simple.
Also I wanted to make it slower than the normal server to 1. reduce the computationfor the server and 2. I want to make a retro feeling, where you have to build your computer parts, wich directly corospond to the sandbox abilitys of the computer.

I thought this could be possible like in the open computers mod for minecraft. I tried to get some information out of their open sourcecode, but since i do not have any clue how they have done it and I dont understand Java.
I hope you can help me.

You're looking at the wrong project. Try Minetest instead of Minecraft.

In particular, this mod implements a LuaController, with a fairly secure sandbox:
https://github.com/minetest-mods/meseco ... controller

Can I utilize LuaController for something like fighting game inputs?