Red Crucible 2 was released in 2012 as a sequel to its predecessor - Red Crucible, released in 2010. A major update followed in 2013, making it one of the most downloaded games in the Apple App Store. The game is a First Person Shooter (FPS) focused on multiplayer gameplay and avoiding any kinds of single player options. It's also completely free to play, aside from the fact that you can use real money to make permanent purchases of weapons and customization items. The alternative is renting the items you want for a limited period of time, using in-game coins which you earn by playing and winning matches.
In terms of delivery, the game is amazing. It uses the common W, S, A, D keys which allow you to move around, while using the mouse to aim and shoot. The graphic and design of the game will stagger you, given the fact that you can play it on your browser without any problems. There are some basic system requirements your computer must meet in order to be able to play the game. Red Crucible 2 can be run it on both Windows and iOS systems. You can either create an account, which takes less than a minute and it's completely free, or play as a guest with no strings attached.
The gameplay itself is pretty diverse for a browser-based FPS - you get to drive tanks, fly helicopters and use lots of different weapons to take down the enemy team. Lagging occurs rarely, but the overall performance depends on the browser you're using. You'll need to install the Unity Web Player in order to play Red Crucible 2 - make sure you get it from the official website, just to be on the safe side.
All in all, it's a great game with a lot of potential if future updates target the changes players ask for. Red Crucible 2 certainly raises the bar for browser-based FPS games.