Sorry, they're reimplementations, not full 1:1 ports from Javascript to Lua. Roblox is also a full game engine. All game scripts are already in Lua and the dev

Sorry, they're reimplementations, not full 1:1 ports from Javascript to Lua. Roblox is also a full game engine. All game scripts are already in Lua and the developers are already using Lua in their games. Their GUI engine is in-house and so would necessitate porting from the web DOM to their game object model, so I doubt it would be a drop-in replacement even if they did the massive amount of work creating an entire duplicate set of language binding for Javascript. GUI driven scripts need to be able to maniulate the game world, and making that happen would definitely be orders of magnitude more work than just reimplementing the good parts of webdev in Lua.