Ironically, Unreal Engine was in large part born from Tim Sweeney's "screwing around with tooling and languages".
UnrealScript has long been dropped in favour of C++, but I'm pretty sure Unreal Engine wouldn't exist today, or would be a very different beast, if it hadn't been for UnrealScript and the Unreal Editor being bundled with the original Unreal and its sequels/follow-ups, and Tim's personal interest and research into how programming languages might improve game development, in much the same way that Jonathan Blow is doing now.
Can I assume your use of the phrase "this person" means you are unfamiliar with Mr Blow, and his track record in game development? You might want to look him up -- he's an interesting character and has developed some interesting and influential games.
UnrealScript has long been dropped in favour of C++, but I'm pretty sure Unreal Engine wouldn't exist today, or would be a very different beast, if it hadn't been for UnrealScript and the Unreal Editor being bundled with the original Unreal and its sequels/follow-ups, and Tim's personal interest and research into how programming languages might improve game development, in much the same way that Jonathan Blow is doing now.
Can I assume your use of the phrase "this person" means you are unfamiliar with Mr Blow, and his track record in game development? You might want to look him up -- he's an interesting character and has developed some interesting and influential games.