Tom Clancy's Rainbow Six Vegas is a great tactical FPS shooter with tons of features and skills.

User Rating: 8 | Tom Clancy's Rainbow Six Vegas PS3
Rainbow Six Vegas changes the series with multiple new features, such as a new health system where the player regenerates health while not taking fire. Though the game has no running which does hurt the game quite a bit. Think about it a shooting game no running... Though the hidden wall perspective is amazing and that unique gamestyle worth playing. The perks you choose are really neccessary in this game and the plan to camp is really large in this game. The player also has various skills, such as the ability to rappel up and down buildings while shooting and the ability to fast rope into an area. This game has 10 game modes Survival, Team Survival, Sharpshooter, Team Sharpshooter, Retrieval, Co-op Terrorist Hunt, Attack & Defend, Co-op Campaign, Assassination, and Conquest. Multiplayer mode supports up to sixteen players.

On the Playstation 3 and Xbox 360 version there is a ranking system, in which the player starts with a certain amount of weapon and outfit choices.
The ranking is very difficult to level up similiar to the Battlefield 2 in other words. Overall this game is very interesting and a game you can play for fun.