1. A Class-based first-person shooter with multiple gamemodes/objectives
2. A multiplayer FPS that 99% of Call of Duty players will hate.
3. A hat-based conga simulator.
4. An FPS that has the time period and art of the 20th century industrial age.
5. IT'S FREE!
If you don't want to playCall of Duty or Minecraft, why not try Team Fortress 2 and Terraria?