Book of Oil

Book of Oil is a video slot developed by Endorphina that operates on a 5-reel, 3-row grid with ten fixed paylines. The theme revolves around oil, barrels, derricks, and wealthy oil barons, featuring a golden and industrial atmosphere. The Book symbol plays a dual role: it acts as both Wild and Scatter. When three or more Book symbols appear anywhere on the reels, they trigger ten Free Spins.

During this Free Spins round, a special symbol is randomly chosen to become the expanding symbol: as soon as it appears in sufficient numbers, it can expand to cover an entire reel, adding winning combinations even if the symbols are not adjacent, as long as the line is active. The Wild cannot substitute for the expanding symbol during the free spins. The game also features a Bonus Pop function, which allows direct access to the Free Spins round for a set cost.

Additionally, after any win, the player has the option to activate a Risk Game to try to double their winnings in a mini-challenge. The maximum win achievable with Book of Oil can reach up to 5,000 times the bet, depending on the version of the game. The game is accessible on mobile devices as well as on computers, with bets ranging from modest amounts to higher stakes, depending on the casino.

You can try it for free in demo mode or play it for real money.