https://www.chess.com/4-player-chess?g=4217440-0
for Upside Down
I like the idea cuber, but promotion should be changed. 1st of all no one ever will promote king or knight if they can promote bishops. 2nd of all if you have long range piece promotion, the game will deteriorate into a check/capture shootout which leads to constant cooperation ("teaming"). also maybe provide some teams example games, as I believe this has the potential to be played both modes. @6_K can you take a look at whether this game can be played anti.
https://www.chess.com/4-player-chess?g=4217440-0
for Upside Down
you can not move the pawns forward
you can