Book of Oil

Book of Oil is a five-reel, three-row slot from Endorphina with 10 paylines and a black-and-gold design built around oil rivers, derricks, tanks and gold-coloured motifs. The game has an RTP of 96.05% and bet options from 0.01 to 50.

The Book symbol acts as both Wild and Scatter. Three Scatter symbols trigger 10 free spins with an expanding symbol chosen at random at the start of the feature. During the bonus round, that symbol cannot be replaced by the Wild, and wins are awarded on active paylines when matching combinations land in adjacent or non-adjacent positions.

A Bonus Pop feature is also included, although its availability can depend on casino jurisdiction. The demo version allows players to play for free and practice before playing for real money while learning the slot’s bonus structure and symbol behaviour.