I've bougth Steel Storm, Burning Retribution in the Software Center, and every time I run it shows the following message:

You have reached this menu due to missing or unlocable content/data

You may consider adding

-base dir /path/to/game

to your launch commandline

I've gone to main menu in the preferences tab and changed the launcher to no avail.

I've tried running it from console, with /opt/steelstorm-episode2/steelstorm, I got:

Game is Steel-Storm using base gamedir gamedata
Steel-Storm Linux 01:07:07 Jun 11 2011 - release
Playing shareware version.
Skeletal animation uses SSE code path
DPSOFTRAST available (SSE2 instructions detected)
Failed to init SDL joystick subsystem:
couldn't exec quake.rc
couldn't exec default.cfg
execing config.cfg
couldn't exec autoexec.cfg
Client using an automatically assigned port
Client opened a socket on address 0.0.0.0:0
Client opened a socket on address [0:0:0:0:0:0:0:0]:0
Linked against SDL version 1.2.12
Using SDL library version 1.2.14
GL_VENDOR: NVIDIA Corporation
GL_RENDERER: GeForce 6150SE nForce 430/PCI/SSE2/3DNOW!
GL_VERSION: 2.1.2 NVIDIA 270.41.06
vid.support.arb_multisample 1
vid.mode.samples 0
vid.support.gl20shaders 1
Video Mode: fullscreen 640x480x32x0.00hz
S_Startup: initializing sound output format: 48000Hz, 16 bit, 2 channels...
Wanted audio Specification:
    Channels  : 2
    Format    : 0x8010
    Frequency : 48000
    Samples   : 2048
Obtained audio specification:
    Channels  : 2
    Format    : 0x8010
    Frequency : 48000
    Samples   : 1024
Sound format: 48000Hz, 2 channels, 16 bits per sample
CDAudio_Init: No CD in player.
Can't get initial CD volume
CD Audio Initialized

If I try -base /opt/steelstorm-episode2/steelstorm says "command not found".