It should be safe enough. If you're worried about the heat, put in on a stand so it gets more air, and/or use smcFanControl to increase the fan speed.
if that doesn't fry your computer, i'm sure that gaming for so long period will fry your brainI would like to know how safe is it for me to play games on it for long periods of time (4-5 hours) while having the power cable plugged in. The laptop gets really hot.
My specs are MBP C2D 17", maxed out HD and RAM.
if that doesn't fry your computer, i'm sure that gaming for so long period will fry your brain