Since this game is a Book of Ra clone, the main question is is it worth to play this one instead when you want your daily portion of Book of Ra. There is very little that Booongo did differently than the template they were copying, and the main advancement is in graphics, which are excellent and are not only an upgrade of this classic title but Book of Sun has one of the best themes in Egyptian-themed slots. I've played this game for a while in order to be able to form an opinion about it, and here are the pros and cons of this Boongo title. Main game and paytable The paytable is quite rewarding and is the main reason why anyone would want to play this game. Sphynx symbol is the best one in the game, and it will pay 500x your bet if you land five-of-a-kind or 100x your bet if you land four-of-a-kind. Two more symbols, Hawk and Wild Scatter, pay 200x your bet if you land five of them. There are two more decent symbols that can pay up to 75x your bet, and the five card symbols are worthless in comparison though you will take the 10x or 15x your bet prize when you land five-of-a-kind. This paytable is identical to Book of Ra Deluxe. Bonus features The Book is a Wild Scatter symbol, so this game draws heavily from the Book of Ra and the general idea of having a very powerful symbol that has multiple roles. When you land three Books, you'll be granted 12 free spins – 2 more than in Book of Ra Deluxe. Before the feature begins, one symbol will be randomly chosen to become the special expanding symbol. If you'd benefit from the expansion of the symbol – e.g. you can form more winning paylines – then the symbol will expand to fill its reel. Book of Sun Slots RTP Theoretical return to player (RTP) isn't known for this slot game, so we may assume the developer decided to keep the RTP low, perhaps even as low as with the original Book of Ra title which had around 92%. But there's no way to know for sure. If the RTP was somewhere near 95%, the developer should have revealed that information to attract the Book of Ra players. Book of Ra Deluxe, which has an identical paytable as this game, has RTP of 95.10%, and each and every player would pounce at the opportunity to play the same game with an improved RTP. But it's unlikely this is the case here. Conclusion Booongo deserve a passing grade for this Book of Ra clone though they didn't do much differently, but the theme is impressive and it looks good on all devices. The main potential of this game is its paytable which can really pay big, and the best thing that can happen during your Book of Sun session is to have Sphynx chosen as your special expanding symbol before the free spins, and then to land five Sphynxes. This would give you 10 paylines worth 500x your bet each, or 5000x your bet total. Compared to Book of Ra Deluxe, you get 2 more free spins here to make this happen, so playing this Booongo game is good for you.