Why is my game so laggy? My game is very laggy and I am on computer, other games are pretty fine.

This is not related to lua. And its because you probably have a lot of parts or you inserted something like a virus.

There are many ways your place could lag: -Excess of parts, even more if unanchored; -Too much script frequency and process: if you have lots of loops with small yield and a huge function; -Script viruses: free models sometimes contains them by the name Vaccine or XxxPwn3XxX, they are coded; to replicate a lot on every game object. You can find anti-virus on free models too, and try to check for scripts inside free models before running the game to prevent them from running.

It is probably a virus/backdoor script in the free models. Use this plugin:

https://web.roblox.com/library/2670956620/Hidden-Infection-Script-Detector