It would have to take a challenge.
but before the challenge the cosmetic of the creations would be shown.
so you get to see them walking staight before they start the challenge.

So cosmetic and functionabilly matters.

[Also may need a size limit]

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2009726901
My RC.

For the carnival Challenge
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2002411202

For the fitness one: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2002373336

Walker!, Make a walker you must have it so you uses legs and not wheels.
You can have wheels on your craft but they can't touch the ground.

No glitch turning or thrusers.
this is my suggestion not a actual challenge