Welcome to the Quake II for MS-DOS port. By Neozeed, [HCI]Mara'akate, and sezero.

1 - What's required?

Pentium 1. At least a 200MHz to play it at ~20-30fps.
At least 48 MB RAM. More for larger mods.
LFN TSR. Use the included DOSLFN.ZIP (can be loaded high with LH DOSLFN.COM)

2 - What works?

VGA (320x200 and 320x240)
SVGA (Banked and LFB)
3DFX OpenGL rendering.
Mouse
Keyboard
Sound Blaster and Gravis UltraSound family
CD-ROM music
OGG and WAV music
Networking (You need a packet driver)
Loading/unloading video driver and game DLLs in DXE3 format.

3 - What works but needs more testing?

Playing in a Windows 9x DOS box.
Several PCI sound cards like AC'97 or HDA (run with -sndpci)
- You can also try using SBEMU, a legacy sound blaster emulator for DOS, with your PCI sound card: https://github.com/crazii/SBEMU
Mouse wheel support. (see info below.)
Hor+ FOV scaling. (see info below.)

4 - What doesn't work

Playing in a Windows NT NTVDM DOS box. If you must, +set sw_mode 1.
Software Renderer: TGA files from maps that were only optimized for OpenGL.
Some models from Whale's WODX server can crash the software renderer. I'm assuming they're custom player models as I tried replaying the same maps later and got no crashes. Until I can spot it, be on the lookout.

5 - Tips and other misc. info

Run /slist2 to get a gamespy list of active servers, or use the new browser menu. Run /srelist to print the previous list. Use CTRL+C to abort.
Don't use EMM386. If you get weird virtual alloc failed errors, it's probably related to this.
Use FastVid for some faster linear frame buffering if you a P1 or P2-era PC. Download it at http://dk.toastednet.org/QDOS/FASTV110.ZIP.
UNIRV can enable custom refresh rates. Great if you have a large CRT monitor. Download it at http://dk.toastednet.org/QDOS/UNIRV142.ZIP.
Gravis UltraSound users: If you have a "stuck" or "repeating" sound as soon you load Q2DOS load Ultramid -Q then Ultramid -Q -F. If you don't have Ultramid for some reason, you can get the fix (with a batch included) at http://dk.toastednet.org/QDOS/GUSFIX.ZIP. You also may need to set s_mixahead to 0.3 and use high DMAs.
Make sure you are using the included CWSDPMI.EXE in your Q2 directory or you may get some issues with running out of memory.
To hear Ogg Vorbis or WAV tracks in game, rip the Q2 CD's audio tracks (2-11) to track02-track11.* and put them in baseq2/music. For the mission pack audio tracks, rip the Ground Zero CD's audio tracks (2-11) to track12-track21.*. Don't bother ripping the tracks from the Reckoning CD, as they're a mix of the tracks on the Q2 and Ground Zero CDs. Everything else will be taken care of internally.
Mouse wheel: The code is from HoT. If you use the latest beta version of cutemouse, which is 2.1b3 (ctmouse21b3.zip), the wheel should work nicely. We tested with the 2.0-alpha and 2.1-beta versions. We automatically detect and use the wheel if it is present. To disable the wheel, use the command line argument -nowheel.
- Note: As of cutemouse-2.1-beta4 version (cutemouse21b4.zip), the wheel is not enabled by default: you must use their /O switch.
Hor+ style field of view (FOV) scaling: Useful for widescreen resolutions. Configured by new cvar fov_adapt: set it to 1 and your FOV will be scaled automatically according to the resolution. It is enabled by default.
MEMSTATS command will report available Physical and Virtual Memory in Mb. You will notice the number will never rise, this is on purpose. Please read the DJGPP FAQ @ http://www.delorie.com/djgpp//v2faq/faq15_2.html for more information on how DJGPP and CWSDPMI work.
Logitch MouseWare drivers in Windows 9x may cause delayed/missing mouse input when played in a Windows 9x DOS box.
Demos recorded from multiplayer can be run with timedemo 1 but to keep the code simple it must be used with the demomap command instead of map. Demomap will set the attractloop mode on which can be used as a hint from the client that a demo is currently playing without having to hack between the server and client. Starting a demo with demomap is easy, i.e. demomap demo1.dm2. The extension must be included.
Some PS/2 mice on certain configurations can cause a performance drop when looking around. Using a serial mouse does not have this issue. Sometimes reducing the sampling rate can help. Use m_ps2_sample_rate CVAR with a value of 0-6 for 10hz, 20hz, 40hz, 100hz, and 200hz respectively. 40hz seems to work best on my machine. Additionally, you can set m_ps2_resolution with a value of 0-3 for 1 count per mm, 2 count per mm, 4 count per mm (default), and 8 count per mm respectively. 8 count can help give a boost to sensitvity. Please note these CVARs are not saved. You will need to add them to autoexec.cfg. If you have problems with these CVARs or the PS/2 detection for this additional code you can start the game -nops2 parameter to bypass it.

6 - 3DFX Notes

Please refer to readme.fx for more details.

7 - Links and Credits

Follow neozeed @ http://virtuallyfun.superglobalmegacorp.com/

Follow maraakate @ http://dk.toastednet.org/

Various code from

cURL -- (http://curl.haxx.se/)
DJGPP community -- (http://www.delorie.com/djgpp/)
Gamespy SDK -- Released publically in 2014.
ggorts -- Ported 3ZB2, Action, Chaos, and DDay to Q2DOS. Banked VGA code and Planar mode help. 3DFX/MesaFX help.
Glide Open Source Project -- (http://glide.sourceforge.net/)
Knightmare -- Ref_soft and ref_gl help, Quake 2 3.24 updates. KMQuake II (http://www.markshan.com/knightmare/)
Mesa -- (http://mesa3d.org/)
Mpxplay PCI Audio library -- (http://mpxplay.sourceforge.net/)
Mpxplay code importing by Ruslan Starodubov (http://sound-dos.ucoz.ru/)
OGG/Vorbis -- (https://www.xiph.org/)
RayeR -- Various DJGPP v2.05 upgrade help, MTRRLFBE (http://rayer.g6.cz/)
R1CH -- R1Q2 (http://old.r1ch.net/stuff/r1q2/)
Sage by Daniel Borca (http://www.github.com/dborca/sage)
Sezero -- WATT32, DJGPP 2.05, 3DFX/Mesa, and several other help. uHexen2 (http://uhexen2.sourceforge.net/)
Yamagi -- Updated game code from YamagiQ2 (http://www.yamagi.org/quake2/)
Berserk, CDawg, Pat Aftermoon, Anthony Jacques, David M. Pochron, Dopefish, GuyP, Jitspoe, MH, MrG, NeVo, Skuller, Riot, Psychospaz, Pooy, Sul, and others.

8 - Tools Used

Cppcheck -- (http://cppcheck.net/)
DJGPP -- (https://www.delorie.com/djgpp/)
GCC -- (https://gcc.gnu.org/)
Microsoft Visual Studio 6 -- (https://visualstudio.microsoft.com/)
Microsoft Visual Studio 2005 -- (https://visualstudio.microsoft.com/)
Microsoft Visual Studio 2019 -- (https://visualstudio.microsoft.com/)
PVS Studio -- (https://pvs-studio.com/)

Q2dos

Install / Use

README