This happens for me too and also same exact thing on red orchestra.

Edit: added system information

Processor Information:
Vendor: AuthenticAMD
Speed: 3300 Mhz
4 logical processors
4 physical processors
HyperThreading: Unsupported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Supported
SSE41: Unsupported
SSE42: Unsupported

Network Information:
Network Speed:

Operating System Version:
Ubuntu 12.04.1 LTS (64 bit)
Kernel Name: Linux
Kernel Version: 3.2.0-35-generic
X Server vendor: The X.Org Foundation
X Server release: 11103000

Video Card:
Driver: NVIDIA Corporation GeForce GTX 660/PCIe/SSE2

Driver Version:  4.3.0 NVIDIA 310.14
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 60 Hz
VendorID:  0x10de
DeviceID:  0x11c0
Number of Monitors:  1
Number of Logical Video Cards:  1
Primary Display Resolution:  1920 x 1080
Desktop Resolution: 1920 x 1080
Primary Display Size: 18.78" x 10.55"  (21.54" diag)
                                        47.7cm x 26.8cm  (54.7cm diag)
Primary Bus: PCI Express 16x
Primary VRAM: 2048 MB
Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
Audio device:

Memory:
RAM: 7963 Mb

Miscellaneous:
UI Language: English
LANG: en_US.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 61608 Mb
Largest Free Hard Disk Block: 51343 Mb

Installed software:

Recent Failure Reports:

Hmm. I was able to change it to 1920x1080 with no issues. AMD Phenom X4 and Nvidia 460. Kubuntu 12.04, x64. I've not tried Red Orchestra yet.

+1

Processor Information:
Vendor: GenuineIntel
Speed: 1867 Mhz
2 logical processors
2 physical processors
HyperThreading: Unsupported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Unsupported
SSE41: Unsupported
SSE42: Unsupported

Network Information:
Network Speed:

Operating System Version:
Ubuntu 12.04.1 LTS (32 bit)
Kernel Name: Linux
Kernel Version: 3.2.0-35-generic-pae
X Server vendor: The X.Org Foundation
X Server release: 11103000

Video Card:
Driver: NVIDIA Corporation GeForce GTX 460/PCIe/SSE2

Driver Version:  4.3.0 NVIDIA 310.14
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 60 Hz
VendorID:  0x10de
DeviceID:  0xe22
Number of Monitors:  2
Number of Logical Video Cards:  1
Primary Display Resolution:  1920 x 1080
Desktop Resolution: 3840 x 1080
Primary Display Size: 20.51" x 11.54"  (23.50" diag)
                                        52.1cm x 29.3cm  (59.7cm diag)
Primary Bus: PCI Express 16x
Primary VRAM: 767 MB
Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
Audio device: Realtek ALC888

Memory:
RAM: 3403 Mb

Miscellaneous:
UI Language: English
LANG: en_GB.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 231708 Mb
Largest Free Hard Disk Block: 201548 Mb

Installed software:

Recent Failure Reports:

This issue can be circumvented by editing the .ini directly

gedit ./.killingfloor/System/KillingFloor.ini

Edit the following fields to your resolution

FullscreenViewportX=1920
FullscreenViewportY=1080

or you could just bring up the console in the game by pressing the ~ key and then type setres 1920X1080 (or whatever you want to set it for). That is what I did.

Just noticed on arch linux wiki page for steam.
https://wiki.archlinux.org/index.php/Steam#Native_Steam_on_Linux

" Killing Floor runs pretty much from scratch, although you might have to change in-game resolution screen as the default one is 800x600 and a 4:3 screen format. If you try to modify screen resolution in-game, it might crash your desktop enviroment. To fix this, please set the desired resolution screen size by modifing your ~/.killingfloor/System/KillingFloor.ini with your prefered editor. "

Also experiencing this issue.

Game initially defaults to 800x600 and using in-game menu to change resolution causes the game to freeze up. Must alt+f2 to console and kill process. Waiting long enough it will kill itself as well. Suggested fixes in this thread will resolve the issue and get the game running at the correct resolution.

Adding to this the fact that once the process is killed, it leaves the ubuntu desktop at the lower resolution. Using display settings to re-set to native resolution will "change" the resolution but everything remains distorted and with the appearance of being a lower resolution. Only way I've found to fix this is to choose a different resolution that has not been used by the desktop or the game in display settings, set it, and then set back to native resolution. Restarting the DE or even the computer entirely does not resolve this issue. I understand this part of the problem is more of an Ubuntu issue than a steam/steam games issue. Just including to demonstrate the issue can be extremely problematic even outside the game itself.

system information:

Processor Information:
Vendor: GenuineIntel
Speed: 3301 Mhz
4 logical processors
4 physical processors
HyperThreading: Unsupported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Unsupported
SSE41: Supported
SSE42: Supported

Network Information:
Network Speed:

Operating System Version:
Ubuntu 12.10 (64 bit)
Kernel Name: Linux
Kernel Version: 3.5.0-21-generic
X Server vendor: The X.Org Foundation
X Server release: 11300000

Video Card:
Driver: NVIDIA Corporation GeForce GTX 460/PCIe/SSE2

Driver Version:  4.3.0 NVIDIA 310.14
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 59 Hz
VendorID:  0x10de
DeviceID:  0xe22
Number of Monitors:  1
Number of Logical Video Cards:  1
Primary Display Resolution:  1680 x 1050
Desktop Resolution: 1680 x 1050
Primary Display Size: 17.05" x 10.67"  (20.08" diag)
                                        43.3cm x 27.1cm  (51.0cm diag)
Primary Bus: PCI Express 16x
Primary VRAM: 1023 MB
Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
Audio device: Realtek ALC892

Memory:
RAM: 7954 Mb

Miscellaneous:
UI Language: English
LANG: en_US.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 142107 Mb
Largest Free Hard Disk Block: 101536 Mb

Installed software:

Recent Failure Reports:
Sat Dec 22 21:13:00 2012 GMT: file ''/tmp/dumps/crash_20121222131258_1.dmp'', upload yes: ''CrashID=bp-d45e5ef8-42f5-45db-bd31-495882121222''
Sat Dec 22 21:13:00 2012 GMT: file ''/tmp/dumps/assert_20121222131300_1.dmp'', upload yes: ''CrashID=bp-ee5d216d-3cf8-4e16-80ad-4e5d72121222''
Sat Dec 22 21:16:27 2012 GMT: file ''/tmp/dumps/assert_20121222131627_1.dmp'', upload yes: ''CrashID=bp-4a5e4205-bedc-468e-8157-40c0d2121222''
Sat Dec 22 21:16:31 2012 GMT: file ''/tmp/dumps/assert_20121222131631_2.dmp'', upload yes: ''CrashID=bp-35e14b8c-9a53-4801-9c8b-0dcc42121222''

Interesting to note that when I played this on Xubuntu, everything worked fine. Resolution changed from the game menu just fine.

I have switched to Ubuntu proper, and now it locks up when I try and change the resolution.

There was another user above that mentioned it worked fine on Kubuntu.

So this seems to be isolated to Ubuntu proper.

Since earlier when I posted my system information I have switched to Arch Linux X64 / Cinnamon ... for unrelated reasons. But this problem still occurred again just like it did on Ubuntu 12.04 and it froze if I changed resolutions in game.

I Have now removed compiz and I am using 2d cinnamon desktop ( to stop screen tearing). Now that I have checked, this changing resolutions problem is now gone.

I can switch resolutions just fine in game now.
Is compositing the problem or is the beta 313.09 drivers the fix ?
It is one or the other I am thinking.

same here:

Processor Information:
Vendor: AuthenticAMD
Speed: 3500 Mhz
6 logical processors
6 physical processors
HyperThreading: Unsupported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Supported
SSE41: Supported
SSE42: Unsupported

Network Information:
Network Speed:

Operating System Version:
Ubuntu 12.04.1 LTS (64 bit)
Kernel Name: Linux
Kernel Version: 3.2.0-35-generic
X Server vendor: The X.Org Foundation
X Server release: 11103000

Video Card:
Driver: NVIDIA Corporation GeForce 9800 GT/PCIe/SSE2

Driver Version:  3.3.0 NVIDIA 310.14
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 119 Hz
VendorID:  0x10de
DeviceID:  0x614
Number of Monitors:  1
Number of Logical Video Cards:  1
Primary Display Resolution:  1920 x 1080
Desktop Resolution: 1920 x 1080
Primary Display Size: 20.04" x 11.26"  (22.95" diag)
                                        50.9cm x 28.6cm  (58.3cm diag)
Primary Bus: PCI Express 16x
Primary VRAM: 512 MB
Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
Audio device: Realtek ALC889

Memory:
RAM: 16032 Mb

Miscellaneous:
UI Language: English
LANG: en_US.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 300386 Mb
Largest Free Hard Disk Block: 194451 Mb

This happens to me too. Nvidia GeForce GTX460 with 310 drivers and Ubuntu with Unity.