super GNG has a patch that fixes the slowdown. It works on real hardware
https://www.romhacking.net/hacks/3473/
Didn’t R-type 3 perform way better than r-type 2?
I was pointing out that the only hardware upgrade that the PC Engine used to keep pace with the SNES was a time machine, to go back in time almost a console generation and run the same type of game faster, with twice as much sprites, larger sprites, with more animation, no constant slowdown, all at a higher resolution.
The dev team said that the PC Engine's outdated cpu made the game harder, because it removed a bunch of slowdown that the arcade version has. What the average "retro" commenter doesn't realize is that the PC Engine version came out only 9 months after the arcade was released. It ran faster than current arcade hardware. The SMS/Mark III version, which people like to say was the best version until the PCE port finally came out, wasn't actually released until 6 months after the PCE version and the same month that the Mega Drive launched.
R-Type III was released 5.5 years after R-Type for PC Engine. Mode 7 is a neat gimmick that other consoles couldn't match, but the game tosses around maybe half as many sprites/action as Super R-Type. Literally around half the time there aren't any enemies onscreen. They usually get killed while entering the screen, keeping their numbers low. But when a string of them sneak by you get hefty slowdown. The better NES/SMS/Game Gear shooters have much more action. R-Type III also abuses tile flipping and is light on artwork. Gradius II for Famicom tosses around 3 or 4 times as much and has several times as much artwork. That's not really keeping pace with real 16-bit consoles.
Gradius III for SNES doesn't get enough credit for actually doing a lot. Sure it has a lot of slowdown as well and was reworked for the hardware, but it still has an impressive amount of action.
I think you may have somewhat misinterpreted my post. I never referred specifically to the PC Engines CPU which of course remained the same throughout it's lifespan. The addition of a CD-Rom unit was a hardware update and as far as I understand it, the system cards provide the system with additional (hardware) memory. I kind of see your logic comparing system cards to larger cart sizes but it's not the capacity of the media that is increasing, it's the systems ability to run it.
The PC Engine doesn't render graphics the same way as SNES and Genesis and doesn't need much ram. That's why it's so good at running animation. The IFU/system card memory doesn't upgrade the PC Engine, it's only the space that segments run out of, same as the FDS or Sega Saturn and its "ram" carts. It's not like the N64's ram expansion.
The PC Engine is actually severely bottlenecked by the CD formats and can do much more on HuCard. Which is why SFII' couldn't be done on Super CD and the Fatal Fury ports are still missing so many background details.