Mario vs Donkey Kong

Theres a chain you can hang onto in the beginning and you have one chance to grab it, otherwise you'll fall into the lava pit after the bridge crumbles. Make sure you grab it and if you don't, you can do it in another life. Otherwise keep climbing up and watch out for the flamethrower equipped toy shyguys. Jump on top of the shyguy to your left and collect the Red Prize. Grab the chain again and jump to the next chain. A second flamethrower equipped shyguy on the right, do the same for the Yellow Prize. This time around go right and use the trampoline to reach the high platform. Take the elevator and duck to go under the blocks. Jump on top of the purple and then grab the chain, use two to go up faster. Grab the Key and jump on top of the two purples to safely cross the spike pit. The door should unlock with that Key, like they all do.