Can you code games with C# on repl.it?
I don't mean console games, I mean can you code an actual 2D or 3D game in C#? Even if there is no game engine
Yes. C# uses Unity. That's a game engine. You can cool 3D games with it. I think on repl.it too.
Yes! But the engine your looking for may not work on repl.it. (The graphics system is very odd to some engines and may need configuration.)