I've lost the vortex game in my iPod nano 3rd generation...?

Yesterday, I was playing the game for an half-an-hour and I saw "Low Power" warning and the iPod turned off. So I connected it to the power adaptor which I bought seperately (as i didn't have a computer always for charging). I left it for sometime and again I opened the games folder. But to my surprise, I could find only two games (iquiz and another one cards game). Is there any way to restore the vortex game in my iPod? I tried searching in Google but I couldn't get any results. Please help me...Thanks..