"Single Player Deathmatch" (g_gametype 2) is the gametype used when playing locally (Singleplayer menu) and selecting the predefined matches against bots (not those in the Skirmish menu). It's also referred as "Unlock tiers" mode or "Campaign" mode.
Like Quake 3 Arena, the "Single Player" mode of OpenArena is not a "story mode", but a series of matches against bots. After starting the game for the first time, in "Single Player deathmatch" players can only access the first four maps, those that are placed in the first "tier". In order to play a map, select the map, the difficulty level, and press "Fight!".
After winning one of these matches, a symbol will appear on its icon, remembering the highest difficulty level you have been able to beat that challenge. Once all of the four maps are won regardless of their difficulty level, a newer tier will unlock, and you will be able to play four more matches, until you reach the final challenge.
The "Excellent", "Gauntlet", "Impressive", "Perfect", "Accuracy", "Frags" medals that you will earn while playing in Single Player Deathmatch mode are stored and shown every time you will enter the "Single Player" menu.
The "Reset" button in the Single Player menu deletes the stored medals and re-locks the tiers.
- It's not necessary to play this mode in order to unlock anything, except this mode own tiers, as nothing is locked in OA itself.
- Single Player Deathmatch is the only gametype not intended to be used in either multiplayer and skirmish modes. Trying to use g_gametype 2 in such ways, there is the risk to get stuck at the end of the match.
- "Single player" may also refer to the Skirmish mode. Even if you have not won any "single player deathmatch" match, you can create "custom" matches using the "Skirmish" button, using different game modes (not only deathmatches, but also Capture the Flag, Overload, Elimination mode, etc.) and maps.
- Since OpenArena 0.8.5, Single Player Deathmatch is the only gametype where you can use the detailed shadows. See Manual/Graphic options#Shadows.
- Multiplayer deathmatches populated with bots are usually obtained using g_gametype 0 and bot_minplayers <n> variables.
- Similar to the "Create" button in Multiplayer mode, but for Single player mode
- It's possible to also launch a match automatically loading the bots without chosing them, using /spmap <mapname> or /spdevmap <mapname> (this one enables cheats) commands.