Doubt about kajam
So is it needed that we need to make the game in replit or use an other IDE or Game engine like unity and unreal engine?
It has to be code, not compiled .exe or .app file, so you can't use game engines such as Unity and Unreal Engine. You can use any IDE, as long as you can run it in replit. When you submit it, it should be submitted on replit too. (Also, I think you can use WebGL builds, but I'm not exactly sure about that).