most of the program is standard assembly, then sometimes it's just manipulating some bits of data in bizarre ways to get to a value, either way it's mostly just consulting the x86 instruction documentation for functionality and encoding.

in terms of the instructions being wild, some of them are chosen, because the opcode matches the byte we need on a specific spot, but other times the instruction is just a randomly chosen one, however it was still usually important that the instruction could take a long operand instead of an immediate 8-bit value