notaz
core, 32X emulation, CD code, ARM asm renderers, dynamic recompilers,
Pandora, GPH device, PSP, Gizmondo ports, CPU core hacks
lots of additional coding (see changeLog).
Homepage: http://notaz.gp2x.de/

fDave
project starter
Cyclone 68000 core and PicoDrive core itself

Chui
FAME/C 68k interpreter core
(based on C68K by Stephane Dallongeville)

Stephane Dallongeville (written), NJ (optimized)
CZ80 Z80 interpreter core

Reesy & FluBBa
DrZ80, the Z80 interpreter written in ARM assembly.
Homepage: http://reesy.gp32x.de/ (defunct)

Tatsuyuki Satoh, Jarek Burczynski, MAME development
software implementation of Yamaha FM sound generator

MAME development
Texas Instruments SN76489 / SN76496 programmable tone/noise generator
Homepage: http://www.mame.net/

Eke-Eke
CD graphics processor and CD controller implementation (from Genesis Plus GX)


Additional thanks
-----------------

* Charles MacDonald (http://cgfm2.emuviews.com/) for old but still very useful
  info about genesis hardware.
* Steve Snake for all that he has done for Genesis emulation scene.
* Stephane Dallongeville for writing Gens and making it open source.
* Tasco Deluxe for his reverse engineering work on SVP and some mappers.
* Bart Trzynadlowski for his SSFII and 68000 docs.
* Haze for his research (http://mamedev.emulab.it/haze/).
* Lordus, Exophase and Rokas for various ideas.
* Nemesis for his YM2612, VDP research and docs.
* Eke-Eke for sharing the knowledge and his work on Genesis Plus GX.
* Many posters at spritesmind.net forums for valuable information.
* Mark and Jean-loup for zlib library.
* ketchupgun for the skin.
* GP2X specific help: rlyeh, Squidge, Dzz, A_SN, Alex and GP32X posters.
* Gizmondo code: Kingcdr, Reesy, jens.l (for the device itself)
* Hardware: craigix (GP2X), EvilDragon (Wiz, Caanoo, Pandora, ...)
  and jens.l (Gizmondo)
* Paul Cercueil for OpenDingux port.
* Inder for some graphics.
* squarepusher for some libretro fixes
* Anyone else I forgot. Let me know if it's you.