It's impressive that the project managed to improve so much in so little time! I hope they manage to keep updating it in the future, though I'm hopeful that a wolfenstein 3D kind of engine is possible on the Neo Geo, I doubt a doom like engine is possible on the platform, it's something I mentioned in the previous update, the motorola 68000 on the neo geo just lacks the power to run the ray casting algorithm that was used on the original doom, at least not without a significant sacrifice of performance. some attempts have been made to make doom run faster, fastdoom improved the performance of the original game significantly, and it's possible to run the game on slow 486 cpus and even some fast 386 cpus at much better framerates with some sacrifices in visual quality. There's also a doom M68k project designed to run the game on 680xx based systems, these ports usually need some kind of accelerator to make the game run faster, the amiga and atari st versions for instance, often suggest accelerator boards with 32 bit cpus, usually a 68020 or faster. By contrast, the sega genesis version uses an FPGA found on the genesis everdrive cart which helps to handle the heavier math.