Previously left positive reviews I think any potential player should be aware of the developers approach to in game currency. I recently learnt that for certain elements of the game I am being asked to pay 40 Gems (this isn't compulsory) but others are only being asked to pay 20 for the same thing. The developers response is to suggest that this is temporary and would 'even it's self out' over time. I think it's fundamentally wrong to charge different amounts to different players.