Btw, shouldn't that be '3 people may participate' ?
Actually, the 2 person thing was when the game was first introduced; they changed it during one of the specials and have kept it at 3 people ever since + my description of the Stone Statue Stage was based only on the episode, not the official description on the site (which was posted AFTER I had finished my translation
)
Once again, I gotta update the OP with the new games + official descriptions.
Though looking at the site, it seems they've gotten rid of the Sand Stage.
Probably due to safety reasons...
Edit: Looks like Sayaka and Sae are set to appear on the 3/16 episode of DERO!