I was playing Infinity blade on 50-60% charge. After an hour of playing it, I got the 20% battery warning. I had speakers on (about 60-70%) while I was playing. My brightness is about 30-40%
He answered your question. Playing an intensive game will drain your battery much faster with several variables effecting it. Heat will cause battery life to drain faster. The processor getting used a lot more will cause poorer battery life and having the screen on with the backlight running will effect battery life. All this combined and you are in a bad boat.
I was playing Infinity blade on 50-60% charge. After an hour of playing it, I got the 20% battery warning. I had speakers on (about 60-70%) while I was playing. My brightness is about 30-40%