Y'know, it really is impressive that OPL's gotten this far in compatibility given the hardware it's running on... correct me if I'm wrong, but I think a fairly large chunk if not a majority of the PS2's library works by now (at least on HDD), right? Minus some minor bugs, the possibility that at least some compat. listings might be outdated and/or were written by people who simply got a game to start while not necessarily playing them from start to finish or the need to tinker with different modes. Like, there isn't that much available RAM to work with on the PS2 and if I'm not mistaken; OPL mostly leans on the IOP in-game which isn't necessarily sandboxed, right? Like there's nothing really stopping games from offloading specific processes to it?
I don't know much about programming but that sounds like a crazy hard thing to optimize around - especially on a very old system which I'd imagine has very little resources available for BIOS/kernel functions as it is. VMC and DSemu are also very impressive feats on their own IMO. What everybody has accomplished while working on this little ol' backup loader is amazing honestly, and I hope to see it improve even further.