flibitijibibo has made an unofficial installer that simplifies installation of the game on Linux. If you own the game, download the installer at http://www.flibitijibibo.com/fedora/installers/flibitSam2_2070b.tar.gz.
To run the game, just run serioussam2 in the installation folder. You may have to chmod +x it first.
To run the editor, just run serioussam2-editor in the installation folder. You may have to chmod +x it first.
To get audio working, move to the root of the Serious Sam 2 installation and make a symlink to your 32-bit libopenal.so. For Fedora, it looks like
ln -s /usr/lib/libopenal.so.1 libopenal.so.0
plr_fFOVOverride = X;
inp_bMouseSmoothing = 1;
inp_bMouseSmoothing = 0;
gfx_iAPI = 2;
gfx_iAPI = 1;
hud_bShowPing = 1
hud_iShowBandwidth = 1
hud_bShowCrosshair = 1
sam_ctMaxDebris = 20
sam_bEnableRagdollDeaths = 0
prf_bShowFPS = 1
net_strConnectPassword = "password"