This game consist of a scatter in a form of a skeleton. 3 scatters appearing anywhere on the reels will land you 10 free spins and pay you x2 your bet. If more than 3 scatters appear you get paid x20 your bet for 4 scatters and x200 your bet for 5 scatters. The scatter symbol also act as wild and substitutes for all other symbols the game has to offer.
When the free spin is triggered, a mystery symbol is selected which will be expanded when appearing on the reels during free spins. The feature can be retriggered when 3 or more scatters/wilds appear anywhere on the reels. Re-triggering the feature happens often as I re-triggered the feature 3 times during the free spins feature, winning me a good $140 on a $0.30 bet.
Now normally most of the time the expanded symbols during free spins feature are normally your low paying symbols like 10,J,Q,K and A. If you play Crystal Mystery you will notice that the low paying symbol does not appear that much during free spins, if you get a high paying symbol as the expanded symbols then 6 out of the 10 free spins the expanded symbol will appear as 3 or more.
I am not a big fan of the Book of Ra slot, but I like this slot. The reason I like this slot is because the main game payout is very good and you win often as well as you can trigger the free spin feature very quickly. I normally win average 7 spins out of 10. Book of Ra triggering the free spin feature can take forever or never happens. So overall I think this slot is great and can land you big wins. I would say this game is medium variance.