Yes the mod is completely free to play now that Steam/Valve has removed the requirement of owning a paid version of a game to play it's source based third party mods. The first step is to install Steam [ link ] and then create a steam account. Second once Steam is installed you need to download/install the Source SDK 2007 from with in the tools under you games library (right click on the steam icon in your system tray, select 'Library', then to the right of the Search [top left] select 'Tools' from the drop down, this will then list the tools available to you to download which you then need to right mouse click on the one listed above and select 'Install Game').
Once you have got a Steam installed and the Source SDK 2007 tools the next step is install/run the SGTLS mod using it's own executable which will put the games files in the appropriate Steam files folder to allow you to play the game. Once you have downloaded/ran the mods Version 1.1 Full Client installation file (sgtls_beta11_full.exe) you are then ready to play the game through Steam. See question #6 for the download link URLS to install the game.
The base install of SGTLS requires 1.5 GB of hard drive space (Excluding Steam, Source SDK Base files, and Custom Content). Once you start playing SGTLS you will be required to download custom maps & files depending on the server you play on. Depending on the servers custom maps you may very well end up needing an additional 1-2 more GB of space on your hard drive.
The minimum recommended computer specifications to play SGTLS are as follows: 1.7 GHz Processor, 512MB RAM, DirectX 8 level Graphics Card, Windows Vista/XP/2000, Mouse, Keyboard, Internet Connection. NOTE: If your system meets the minimum specifications to play the mod it still may play undesirable for you on certain servers or require you to lower the games settings for it to play more smoothly. The recommended setting to play SGTLS are as follows: Pentium 4 processor (3.0GHz, or better), 1GB RAM, DirectX 9 level Graphics Card, Windows Vista/XP/2000, Mouse, Keyboard, Internet Connection
The SGTLS mod download is available in a variety of places on the Internet. It doesn't matter where you download it from but the important thing to remember is to verify you are downloading and running the installation for the 1.1 version of the mod. If you install any other version you won't be able to join any of the servers unless you upgrade it. You can install the mod using international/European download sites provided by the mods developer here & for North American based players you can download the mods installation file (and other mod related files) here.
Log out Steam, Download the mods 1.1 version installation file, run the installation file, restart Steam, go to your Library page, click on "Stargate: The Last Stand" in your games list and then click the 'play' button.
The simple answer is because of Stargate licensing regulations. Only a mod that has the licensing for Stargate from MGM (which cost over a million US dollars) would be able to be downloaded/updated via a gaming portal like Steam. Thus due to licensing and Non-disclosure agreements any mods that are made must be manually downloaded/installed.
No, SGTLS will not run on a Macintosh operating system. Just in the last year the Steam platform and some of it it's games became available to Macintosh system users. Seeing how it would take a ton of work to revamp/recode the mod to run on a different operating system then Windows the likeliness of it ever being available to Macintosh system users is almost non-existent.
This is either because the player left the server as you where joining it or because the server utilizes a spectator bot or in game bot that leaves the server automatically when a real player joins. If you join a server and it is empty it is recommended you stay in the server for a few minutes to see if other players join it (they usually do depending on the player base available to play at the exact time you are on).