Yes, they are solving the storage and RAM challenges partially by throwing CPU at it: not using native pointers, switching between multiple struct sizes where t

Yes, they are solving the storage and RAM challenges partially by throwing CPU at it: not using native pointers, switching between multiple struct sizes where the original had one, compressed integer values, etc., also they restructured drawing to happen in slices as the beam travels, which must have its costs. Also I wonder whether original Doom relied on some GPU hardware, whereas here everything happens in software. RP2040 doom also has to emulate the sound hardware, and handle lots of interrupts to initialize the DMA for each individual video scanline. OTOH they are actually overclocking the RP2040 at 270Mhz.