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Castle Builder

RTP 96.47%
Play Microgaming Slots
Reels 5
Paylines 15
Min bet size
Max bet size
RTP 96.5
Wild symbols Yes
Free spins No
Bonus Yes
Jackpot 140000 coins

Castle Builder Slot Review

The Castle Builder slots game can be found at Microgaming casinos. Microgaming as a standard now publish the slots house edge information of all their games at any online casino that holds a UKGC license (this is a requirement for all UKGC licensed casinos. As such we can say that the House Edge of Castle Builder is 3.53%. When playing at any venue that does not hold a UKGC license and does not specifically publish the Return to Player information for their game, this information should be used as a guideline only as we cannot confirm whether or not this game is configurable.

Build your empire and reap the rewards of being at the top of the pyramid.

This game is a 5 reel game with 15 paylines.

The ‘Builder’ symbol is Wild.

Castle Builder uses a unique bonus system. During each spin you can receive the ‘Resource’ symbol. If you receive 2 or more of these on an active payline, the Castle to the left of the reels gets built up a little more. Each time this happens the three prize pots at the top of the reels are increased. The more Resource symbols you receive on the payline the bigger the increase to the prize pots. When the Castle is finished 3 suitors will come to marry the princess. Select one of the suitors to win one of the prize pots.

Each time you finish building a Castle you’ll move on to building the next Castle. Each Castle requires more Resource symbols than the last. There are 3 kingdoms that require your building skills and 10 castles in each realm. After the kingdoms are complete, you move on to building castles for the Emperor. There are 5 Castles to build for the Emperor and each of these requires substantially more Resource symbols than the previous Castles.

Once the Emperor’s Castles are completed the game is complete and you have to start from the beginning again.


Castle Builder has a reasonable House Edge and while the bonus feature is remarkably repetitive it is unusual and different. The banking to win the feature is interesting and keeps you wanting to play.

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