Tom Clancy's Rainbow Six (PC) FREE Only pay £2.99
You command an elite anti-terrorism force through a series of stealth and action missions. Sometimes you will need to sneak through a foreign embassy in the dark with your night vision goggles on, while other times you'll need to launch a full-on weapons attack on your enemies. The game does both types of missions well, but you'll have to spend some time planning with your team before you start each level. Plotting out missions in advance and positioning team members lends a unique real-time strategy feel to the already excellent shooter aspect of the game.
As the team leader, you are solely responsible for making sure each mission goes well. Direct and protect your squad, save any hostages who might be hanging around, and accomplish your main mission objectives.