Mario took a running start. The goal was the warp zone, a piping error that, if accessed correctly, would let them bypass the tedious fire-bars of World 8. But if the calculations were off by a single pixel, they would fall into the "void"—that blue abyss where the code stopped rendering reality.

In the original game, the difficulty spiked at World 4. In The Lost Levels , it spikes at World 2. In "MarioNES 1.5," the curve is linear but steep. The hack utilizes what designers call "false friendliness." Coins are placed in long, enticing trails that lead into bottomless pits. Springboards are positioned directly under falling Thwomps (ported from Mario 3 via code injection).