What elements can I use in my game?
You can create your own or simply use those created by others and available. You can even use commercial gaming assets.
Just make sure you give the appropriate credit when necessary and indicate the assets you use and don't own.
What engine/tool should I use to create my game?
It doesn't matter. As long as your game is playable on a Windows system, you can use any engine.
So basically, you can use game engines like Unity, GameMaker or Godot, etc...
Are there any other limitations?
Submitted games cannot contain nudity or sexually explicit themes.
Hate speech or any other type of harassment will also not be tolerated.
Regarding the language of your game, we would recommend to make it in English, but you are free to make it in any language possible.
Games that contain too much gore and violence should have warnings on their pages.
A person can be part of several teams, and may have proposed several games.