See first video for more details.
Quite recently, this walkthrough became just a "try to survive" rather than "100% everything". Also, there's a newer version of this hack, with only subtle differences, so I'm sticking with Delta for this walkthrough.
0:04 Descent to Darkness: Fast paced action filled level. This level has you making very tricky jumps. This is already a sign that World 4 is where things start getting challenging. Welcome to the real beginning!
2:49 Lava Fortress: This level even features the ever infamous P-Balloon. The trick on the last one is to fly on top of the nearby Chuck, and have him running left by the time you hit the block that has the last balloon, knocking him out in the process.
6:30 Hellish Bridge: There's still more hell to come. Features bullets, footballs, and other hellish things to be re-used later on.
8:25 Magma Megalomania: One of the few levels I've ever built to have a fork in the road that led to the same exit. The first half is standard fare, then you choose left or right. Except I used a savestate where the midpoint was, went left, loaded that state, then went right.
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