gauauu wrote:
Holy cow, that's fast. I'm impressed.
Having a completely developed game working already helped immensely.

The bulk of the work was just translating Z80 instructions over to 6502. Pretty boring work, but I enjoyed seeing the entire insides of the original game as I did it, and some times I had to get a bit creative with the 6502's advantages (X/Y indexing mostly) over the features it lacks (16 bit registers). But the most original work came from dealing with the hardware limitations of the NES, and balancing compromises against what I felt was essential to retaining a completely accurate arcade experience.
Bregalad wrote:
But does your port use more than 16KB of PRH-ROM ? Remember that for Nintendo it might have been unacceptably costly to use 32KB at the time.
It's 32KB, though a large part of it is used by two samples, the DK grin and the boom sound, which I felt needed to be DPCM samples to respect the arcade version.
The idea was never to build a "better version" using the same hardware limitations, and I also ended up using ekstra work RAM from the cartridge, though this is mainly because of #1. I wanted the game to remember high scores, and #2. The arcade game does collision detection by reading from the "nametable" in video memory, something the NES obviously can't while drawing a screen, so I opted to use work ram to buffer the entire video memory of the arcade game. I could probably change a lot of things to work around it, but it was more important for me to have the game logic work as close to the original game as possible.
However, I'm pretty happy, and relieved, that I was able to fit the game's graphics (which has a lot more potential space in the arcade game) into a single 8KB CHR-ROM without using any bank switching. It's extremely tightly packed.
I seemed to recall that the original had 4 levels and the NES port only 3 levels (which is way worse than graphics resolution changing as a change), however I only see 3 levels in your youtube video.
rainwarrior wrote:The pie factory is in there. Skip to ~8mins. It doesn't appear in the first few loops, but that's how it was in the arcade too.
Exactly, rainwarrior

The original stage sequence is "barrels"->"pies"->"elevators"->"rivet", but the US arcade release changed it around so the pie/cement factory and elevator stage were both skipped on the first level, and only added on the third and second levels respectively. As you'd get further into the game, barrel stages would also appear every second screen, as they are the hardest.
While working on the game, I got to try the level 1 versions of both the pie factory and elevator stage, and those are extremely easy compared to the other screens, so I can honestly understand why they changed it, even though the new stage order makes very little sense.
In general, the US final revision of the game is considered the true competitive version of the game, and with good reason.