Then there are the life crystals. The checkpoints of Revelations 2 as in Revelations, are at the beginning of the phase. If the phase lasts 20 minutes and die after 18 minutes, you have to repeat the whole entire section, and this does not always like everyone, so you can buy some crystals of life through daily challenges or paying with realpara money back on level just where you died without penalty.
So do not have to buy anything. If you want to, there it is, but do not have to do whenever you're enjoying the game. "
They are not mandatory, and you can earn crystals in game, but this is still a new low