Every sandbox-game is welcome in this jam.

Becuase the only rule is that your game has to be a sandbox-game, here is the Wikipedia-description of that kind of game:

"A sandbox game is a video game with a gameplay element that gives the player a great degree of creativity to complete tasks towards a goal within the game, if such a goal exists. Some games exist as pure sandbox games with no objectives; these are also known as non-games or software toys. More commonly, sandbox games results from these creative elements being incorporated into other genres and allowing for emergent gameplay. Sandbox games are often associated with open world concepts which gives the player freedom of movement and progression in the game's world. The "sandbox" term derives from the nature of a sandbox that lets children create nearly anything they want within it."

The only crateria that matters is the fun your game makes :)