Developers:

Engine, frontend, net server: Andrey Korotaev <unC0Rr@gmail.com>
Many frontend improvements: Igor Ulyanov <disinbox@gmail.com>
Many engine and frontend improvements: Derek Pomery <nemo@m8y.org>
Drill rocket, Ballgun, RC Plane weapons: Martin Boze <afffect@gmail.com>
Mine number and time game settings: David A. Cuadrado <krawek@gmail.com>
Frontend improvements: Martin Minarik <ttsmj@pokec.sk>
Frontend improvements: Kristian Lehmann <email@thexception.net>
Mac OS X/iPhone port, OpenGL-ES conversion: Vittorio Giovara <vittorio.giovara@gmail.com>
Many engine and frontend improvements (and bugs): Richard Karolyi <sheepluva@ercatec.net>
Gamepad and Lua integration: Mario Liebisch <mario.liebisch@gmail.com>
Many engine improvements and graphics: Carlos Vives <mail@carlosvives.es>
Maze maps: Henning Kühn <prg@cooco.de>
Engine and frontend improvements: Henrik Rostedt <henrik.rostedt@gmail.com>
Lua game modes and missions: John Lambert <redgrinner@gmail.com>
Frontend improvements: Mayur Pawashe <zorgiepoo@gmail.com>
Android port: Richard Deurwaarder <xeli@xelification.com>
Android netplay, portability abstraction: Simeon Maxein <smaxein@googlemail.com>
WebGL port, some pas2c and GLES2 work: Meng Xiangyun <xymengxy@gmail.com>
Video recording: Stepan Podoskin <stepik-777@mail.ru>
Campaign support, first campaign: Szabolcs Orbàn <szabibibi@gmail.com>
Keybinds, feedback, maps and hats interfaces: Drew Gottlieb <gottlieb.drew@gmail.com>
Login dialogs, frontend improvements: Ondrej Skopek <skopekondrej@gmail.com>
Icegun weapon: Julia Struchenko <urbertar@gmail.com>
iPhone/iPad ports: Anton Malmygin <antonc27@mail.ru>
Battalion style: Anachron <Anachron14@gmx.de>
Scripting, engine, frontend improvements, some missions: Wuzzy <Wuzzy2@mail.ru>
Theme customization improvements: KoBeWi

Art:

John Dum <fizzy@gmail.com>
Joshua Frese <joshfrese@gmail.com>
Stanko Tadić <stanko@mfhinc.net>
Julien Koesten <julienkoesten@aol.com>
Joshua O'Sullivan <coheedftw@hotmail.co.uk>
Nils Lück <nils.luck.design@gmail.com>
Guillaume Englert <genglert@hybird.org>

CopherNeue <ppicondo.cvac@gmail.com>
Hats: Trey Perry <tx.perry.j@gmail.com>

Sounds:

Hedgehogs voice: Stephen Alexander <ArmagonNo1@gmail.com>
John Dum <fizzy@gmail.com>
Jonatan Nilsson <jonatanfan@gmail.com>
Daniel Martin <elhombresinremedio@gmail.com>

Translations:

Brazilian Portuguese: Romulo Fernandes Machado <abra185@gmail.com>
Bulgarian: Svetoslav Stefanov
Czech: Petr Řezáček <rezacek@gmail.com>
Chinese: Jie Luo <lililjlj@gmail.com>
English: Andrey Korotaev <unC0Rr@gmail.com>
Finnish: Nina Kuisma <ninnnu@gmail.com>, Janne Uusitupa
French: Antoine Turmel <geekshadow@gmail.com>, Clement Woitrain <sphrixclement@gmail.com>, Matisumi
German: Peter Hüwe <PeterHuewe@gmx.de>, Mario Liebisch <mario.liebisch@gmail.com>, Richard Karolyi <sheepluva@ercatec.net>, Wuzzy <Wuzzy2@mail.ru>
Greek: <talos_kriti@yahoo.gr>
Italian: Luca Bonora <bonora.luca@gmail.com>, Marco Bresciani <m.bresciani@email.it>, Gianfranco Costamagna <costamagnagianfranco@yahoo.it>, Enrico <enricobe@hotmail.com>
Japanese: ADAM Etienne <etienne.adam@gmail.com>, Marco Bresciani <m.bresciani@email.it>
Korean: Anthony Bellew <anthonyreflected@gmail.com>
Lithuanian: Lukas Urbonas <lukasu08@gmail.com>
Polish: Maciej Mroziński <mynick2@o2.pl>, Wojciech Latkowski <magik17l@gmail.com>, Piotr Mitana, Maciej Górny
Portuguese: Fábio Canário <inufabie@gmail.com>
Russian: Andrey Korotaev <unC0Rr@gmail.com>, Vitaly Novichkov <admin@wohlnet.ru>, Anton Malmygin <antonc27@mail.ru>
Slovak: Jose Riha
Spanish: Carlos Vives <mail@carlosvives.es>
Swedish: Niklas Grahn <raewolusjoon@yaoo.com>, Henrik Rostedt <henrik.rostedt@gmail.com>
Ukrainian: Eugene V. Lyubimkin <jackyf.devel@gmail.com>, Igor Paliychuk <mansonigor@gmail.com>, Eugene Sakara <eresid@gmail.com>

Special thanks:

Aleksey Andreev <blaknayabr@gmail.com>
Aleksander Rudalev <alexv@pomorsu.ru>
Natasha Korotaeva <layout@pisem.net>
Adam Higerd (aka ahigerd at FreeNode)