After playing the demo, here: http://www.scirra.com/demos/ghost-shooter/default.aspx
and turning off the tab to test that "pause" feature, I returned and noticed the FPS = 1 while playing the game, the graphic was working perfectly, no lag, etc, but the real frame rate was not updated after returning back to the game tab.
Also, I was out of the tab for more than 30 seconds.
Core 2 Duo, 4gb ram, hd 7200 rpm sata 2
Chrome: update 15.0.874.120 m
Video Card: Radeon HD 5670