In this unofficial update two new experimental libretro cores have been added. TyrQuake (Quake) & NxEngine (Cave Story aka Dōkutsu Monogatar). These cores are a WIP so beware there are issues that have not been ironed out yet. Some of those issues you can see below, consider these previews of what is to come in the future as they progress before being added to the official builds of RetroArch. Thanks goes out to the entire RetroArch Team for all their hard work and pete_uk for this compile for the people who do not have the means to make a compile on their own.
Quote from Pete_uk
Many thanks to SquarePusher, TheMaister and the rest of the Libretro team.
New Core TyrQuake - Quake 1 and Hipnotic & Rogue mission packs (WIP)
New Core NxEngine - CaveStory (WIP) No Sound-FX
Final Burn Alpha - Arcade
FCEUmm - Nintendo NES / Famicom
Gambatte - Nintendo Game Boy & Game Boy Colour
Genesis Plus GX - Sega SG1000, Master System, Game Gear, Genesis and Sega CD
Mednafen NGP - SNK NeoGeo Pocket & Colour
Mednafen PCE - NEC PC-Engine / SuperGrafx
Mednafen VB - Nintendo Virtual Boy
Mednafen WSwan - Bandai Wonderswan
Nestopia - Nintendo NES / Famicom & FDS
PrBoom - Doom 1, Doom 2, Final Doom etc.
Snes9x Next - Nintendo SNES
VBA Next - Nintendo Game Boy Advance
- Quake Files
--- PAK0.PAK / PAK1.PAK (Must be acquired)
------ Expansion Rogue: (PAK0.PAK - Must be acquired)
------ Expansion Hipnotic: (PAK0.PAK - Must be acquired)
- Cave Story files
--- These files are needed. (launch the EXE from RetroArch)
Download - RetroArch 0.9.8.4 Unofficial Compile by Pete_UK
Code Source: Libretro @ github.
Source: PS3Crunch Forums