So I just beat the hiscore on Moolina's level and unlocked the robot level - I found that holding the Playdate the normal way and blowing on the mic was most effective :)
On Creamy Circuit (another wee typo there, the level name says "Creamy Circut" (unless that's deliberate)), the effects were fine the first try but on subsequent tries, the Neopolitan didn't give the slow effect and the Choc Chip made me use the mic instead of the crank. I'll try it a few more times tonight to see if it happens again.