Best Thunder Slots

Five rows give the fruit and BAR symbols plenty of company on just three reels. The symbol to watch is the gold coin with a lightning bolt. In Thunder Coins XXL: Hold and Win, it can collect the values sitting alongside it. Its theoretical return to player is 95.60%.

• Thunder collection. When the Thunder symbol lands with a bonus coin, it collects the bonus values in view. Those can include a Mini, Minor, Major or Grand jackpot.
• Three starting respins. A bonus symbol on each reel opens the Hold and Win round with three respins. The gold pile above the reels offers another way into the round when a bonus symbol lands.
• Fifteen winlines. Fruit, sevens and BARs form line wins across the three tall reels, so there’s something to watch even on a spin without a coin.

Zeus stands beside a marble temple with five reels and three rows. His thunderbolt slot gives coin symbols two different jobs. A group of six can open the respins, while smaller groups can move you up a ladder during free spins.

• Thunderbolt Power Re-Spins. Six or more Credit Coins start the feature. Two windows open at first, and special symbols can unlock two more.
• Lightning Ladder. During free spins, a landing of five or fewer Credit Coins advances the ladder. Watch the meter beside the reels to see which award is in reach.
• Four-window Grand. Fill all four respin windows to collect the 10,000x Grand along with the values on the coins. The Grand accounts for 10,000x of the possible 12,000x maximum win.

Thunder Mega Sevens looks like a neon fruit machine, right down to the bright red sevens. There are 20 winlines across five reels. When numbered bonus symbols land, look up. The wheel above the machine can multiply their combined value.

• Wheel of Thunder. Five or more bonus symbols in the base game trigger the wheel. Each carries a value of 1x to 5x the spin amount. The wheel multiplies their sum.
• Wheel respins. The 2x + Respin and 3x + Respin segments apply their multiplier and give the wheel another turn. The largest single multiplier segment is 12x.
• Free spins. The feature can award 10, 15 or 20 free spins. Bonus values accumulate above the reels, and even one bonus symbol during the round qualifies that total for a wheel spin at the end.

Tiki Thunder trades lines of fruit for a five-by-five grid of carved masks. Follow the matching colors up, down and sideways. When the reels cascade after a win, the matching symbols clear and new ones drop into their places. Gold Coin play has a theoretical RTP of 94.07%.

• Clusters of five. Five or more matching symbols form a cluster win when they touch horizontally or vertically. Wilds can join the cluster, so check the gold mask between two patches of the same color.
• Multiplier meter. Consecutive wins move the meter above the grid. When its Gold Mask feature activates, it adds one to three Wilds before the meter moves to the next multiplier.
• Giant symbols. A two-by-two symbol counts as four matching symbols, and a three-by-three counts as nine. A single oversized mask can change the shape of a cluster.

Thunderline Express: Supercharged puts a locomotive above three compact reels. Keep an eye on the middle reel when gold coins land on either side. The Coin Train collects their values, and more than one train can collect the same coins during the bonus. Gold Coin play has a theoretical RTP of about 92.77%.

• Lightning Booster. Wild symbols advance the counter above the reels by one each, up to 25. In either Hold & Win feature the counter can spend points to multiply individual coin prizes by 2x, 3x, 4x or 5x.
• Coin Train. The train lands on the middle reel. During Hold & Win, trains stay in place and each one collects the golden coins that land during the feature.
• Jackpot train. Jackpot Hold & Win uses Jackpot Coins and Jackpot Trains. The four fixed jackpot tiers run from the 15x Mini through the 25x Minor and 100x Major to the 500x Grand.