What are the possibilities of roblox lua; how much can roblox lua do?

I'm wondering what rlua can do. Is it possible to have super complex code such as knocking over a door and then using a tool to make 'time go backwards', which would move the door back where it was before it was knocked over in the same path. What I mean by that is if the door got knocked over and fell backwards, it would then come back to the front against gravity.

Of course this would take a lot of time and possibly lag, but would it be possible?

Yes Lua is a general purpose language and can be used to create anything. The limitation is what Roblox provides and since they provide the ability to both get and set the position of parts this is possible. Depending on your needs and implementation and hardware it might lag or it might not.

Most things are possible in Roblox Lua. There are some limitations. But this question is a opinion based answer, not a solution to problem answer so there is really no answer to this.That's just my opinion

Anything from game creating to ip logging. Ip logging is about where it stops as you can use an external web site using httpget to ip log.