We need 15 Star Coins to unlock this level. It's an auto-sidescroller with Super Mario 3 music. There are several yellow cracker-like platforms moving to the left. Over a couple of brick blocks is the first Star Coin. To get the second Star Coin, we let the dropping platform drop a little, then jump to get it and bounce off the green enemy to safety. We then use an orange Mystery Box to warp. The sidescrolling stops when we reach the orange Mystery Box and starts again when we warp. The midpoint is here. I lingered by the midpoint and died.
Take 2- We move forward onto yellow rectangular platforms coming towards us. Towards the end of it, on the left is the third Star Coin. There's another orange Mystery Box to warp us to the flagpole.