Then you didn't check everywhere. I haven't played this game in like 6 months, but I remember how linear it is. Check your map. It always shows any secret rooms, even if you can't see it. The map is how you find everything.
The Commandments of Android
1) Open RAM is wasted RAM - Don't use Task Killers
2) Cheap devices are cheap for a reason. Don't expect high end performance.
3) Boot Loop = Wipe.
4) There are no viruses for android.