There are 9 galleries in total, and these can be done on any difficulty. In Survival, you will keep doing laps of the map until you die and the objective is to survive for as long as possible. Since these can be done on any difficulty, change to easy difficulty in the options menu. Some of these are quite easy, though the first gallery is not one of them. Once you acquire gold on the first level, you should have the skills necessary to get through most of the rest of the Survival galleries. Tips can be found HERE.