This type of map is called a "dead simple"-map.
1. One large room.
2. Simple structures within the room that offer cover to players.
3. The full range of weapons and powerups.
4. The full range of support items like ammo, armor, and health.
5. All the most useful items are out in the open, away from cover.
6. Respawns are in safe areas, and away from the most useful items.