Doppelt so clever appears to follow the model of 2018's Ganz schön clever. Each turn the active player rolls six dice, chooses one of them to mark off a space on their scoring grid, place any dice with lower numbers on the side, then re-rolls any remaining dice. After the active player chooses at most three dice, then the other players chooses one of the set-aside dice for use on their scoring sheet.
Doppelt so clever has five new dice-marking challenges and a new action beyond the re-roll and "use one more die" actions of the earlier game.