on the normal way, Mortal Kombat Trilogy is only full compatible on original PS1 system, even on original PS2 or PS3 system is this game not perfect working and crash mostly and crash always on the ending screen. So I can only play my PAL copy perfect on my original PS1 system. This is one of the rare obscure PSX titles, everyone has trouble with it. Use instead of it Mortal Kombat 3 PSX, this works great also the Beta copy, otherwise Ultimate Mortal Kombate 3 on emulator for SNES or Mega Drive.
I had see a Android version for UMK3, maybe someone can port it, would be great. And for sure Mortal Kombat Gold PAL copy was more bad with errors. Very bad we have no Sega Saturn emulator with MKTrilogy with alternate engine.
Mortal Kombat Trilogy seems to work fine with PCSX ReARMed, I haven't tested it for long though, I do wanna test Bugs Bunny Lost in Time with it sometime because I've been playing it on Adrenaline and it runs slow, a few areas are glitchy too, idk why...
However, for me personally UMK3 is no replacement for PS1 Mortal Kombat Trilogy because I like playing as the additional characters especially playing as the bosses which the N64 version lacks, luckily there has been a Rom Hack known as Ultimate Mortal Kombat Trilogy for the Mega Drive that I've been relying on to scratch that itch for over a decade, it does not run on real hardware due to using additional RAM that is beyond the capabilities of a real Mega Drive, making it incompatible with many emulators especially older ones, however nowadays it seems to run on any MD emulator I throw it on, at least I can confirm it runs via GensPlus GX and even the PSP MD emulator.
Emu4Vita Arch v.1.08 - pcsx_rearmed
https://www.rinnegatamante.eu/vitadb/#/info/1094
https://gitee.com/yizhigai/Emu4Vita/releases
NEW UPDATE -> PCSX-ReARMed_v1.10.vpk
So far I remember not sure anymore, the untouched Beta copy for Biohazard 1.5 was a ISO file and not working with Emu4Vita, but was working with Retroarch.... somehow
Problems maybe fixed in the update version, I had not test the new version so far, need time.
Funnily I HAVE tested both Resident Evil 1.5 and BioHazard 1.5 last night, both seem to run via PCSX ReARMed, both .bin format, I always convert my PS1 games to bin/cue format, I have a couple of good tools to rip and convert legacy disc based systems (except for Dreamcast) you'd be surprised how many ISOs are ripped poorly floating in Roms sites, had to fix several of my own...
Anyway, I didn't play for long because I only tested a couple of games but yeah I guess they got fixed, Friday Night Funkin also worked both the official PS1 version and the alternate PS1 version, only two games did not run from my very small testing, Jikkyo Oshaberi Parodius crashes after the Konami screen, and... umm... Yakyuuken Special
(I only tested it as a joke tbh, it does not bother me that it crashes at the opponent select screen)
RetroArch Nightly
https://www.rinnegatamante.eu/vitadb/#/info/186
https://buildbot.libretro.com/nightly/playstation/vita/
Nightly is for testing, use Stable Version when you dont know what to do. Otherwise Retroarch is great but not perfect and has many mistakes here and there.
Retroarch is the only one for Vita, where you can SWAP PSX ISO Discs, so Disc 1 to 2 or 3... I need it for Metal Gear Solid german version, since Adrenalin need a compiled ISO 2 Discs into 1 and this is not untouched.
X-Files the Game (4 Discs) is working best with Retroarch, this game is not working on Adrenalin or PS2 or PS3.
Duke Nukem Land of the Babes ''Beta Version'' Planet of the Babes was working very bad on Adrenalin and water effects was bad. But perfect working on PS3 system with CFW. Not good working on PS2 with FMCB.
was testing all this stuff last year, so its not fresh in my head....
Yeah RetroArch is a nice substitute but I was never a big fan of how slow it starts up and to swap games and how busy it is to navigate, but mostly due to how taxing on older systems it can be, I can understand its value especially nowadays and since 2020 I started relying on it more on newer hardware but on older hardware like the Wii and PS Vita it's just too slow to use for a simple NES game so I tend to use standalone emulators whenever available.
I'll be honest, I don't think I have tested any of the multi-disc PS1 games with adrenaline, it was my understanding they work fine, I downloaded a bunch of them from the PSN store and converted a bunch of them but don't believe I ever got around sitting down and testing a full multi-disc game on my PS Vita, some games use 3 discs like FFVII and Super Adventure Rockman... I believe Policenauts too (or was it the Saturn version that used 3 discs? I forgot) however I didn't know some PS1 games used four discs though, on Game Cube afaik 2 discs were the limit, but I know Phantasmagoria for the Sega Saturn used 8 discs.