Dr Zappo

Dr Zappo is a Hacksaw Gaming slot that puts a mad-science spin on mechanics. EyeBall symbols fire across the reels, turn regular icons Wild, and collect multipliers along the way. Three bonus rounds expand on this concept, all presented through colorful comic-style visuals and an eccentric laboratory theme.

Overview

Dr Zappo uses a 5×4 grid with 14 paylines and comes with high volatility. The RTP stands at 96.31%, while wagers start at €0.10 and go up to €100 per spin. The maximum win reaches 10,000x the stake.

Gameplay Features and Bonuses

Wild EyeBall Symbols: EyeBalls appear only on the fourth row and activate from left to right. Each one fires horizontally, diagonally up, or diagonally down, then turns pay icons in its path into Wilds. New Wilds may also receive a multiplier from 2x to 200x. After its shot, the EyeBall itself becomes Wild.

Wild Multipliers: If an EyeBall hits an existing Wild, that symbol receives an added multiplier from 1x to 200x. A Wild that already has a multiplier receives the new value on top of its current one. Values from several multiplier Wilds in the same win combine before the payout.

Energy Fields: 3 Energy Fields appear along the left, top, and right edges. EyeBalls can rebound from them and continue across the grid. Pay symbols struck after the rebound turn Wild, while a direct field hit sends the EyeBall back along its original path and adds multipliers to Wilds.

FS Scatter Symbols: These figures unlock 3 Free Spins rounds, each with 10 initial spins:

• 3 FS Scatters unlock Eyeconic Bonus
• 4 FS Scatters unlock No-Brainer Bonus
• 5 FS Scatters unlock Hidden Epic Bonus: It's Electrifying

Note: FS Scatters and EyeBalls cannot appear on the same spin.

Eyeconic Bonus: EyeBalls have a higher chance to appear during the 10 Free Spins. 2 extra Scatters award 2 more spins, and 3 award 4.

No-Brainer Bonus: This 10-spin round lets each active EyeBall fire in two directions. The same additional spin values apply.

Hidden Epic Bonus: It's Electrifying: This round also gives each EyeBall 2 shots, but at least 1 EyeBall appears on every Free Spin. FS Scatters cannot appear here.

FeatureSpins and Bonus Buy: 4 paid options provide altered base-game conditions or direct bonus access:

• BonusHunt FeatureSpins: For 3x wager, players get a 5x higher chance for a bonus trigger.
• ZigZag Zappo FeatureSpins: 100x wager guarantees at least 2 EyeBalls per spin.
• Eyeconic Bonus Buy: For a 50x wager, players can directly access the bonus.
• No-Brainer Bonus Buy: A 200x wager price grants direct access to the bonus round.

Design and Soundtrack

Dr Zappo takes place on a bizarre city street where mad science seems to have taken over every corner. Comic-book art, saturated colors, strange storefronts, and oversized laboratory equipment set the tone, while eccentric characters surround the reel grid. The symbols add more personality through ray guns, bombs, unusual creatures, and character portraits, alongside the simpler 10-A card ranks. A chunky blue machine frames the 5×4 grid and reinforces the laboratory concept. Energetic music and electric audio cues round out the presentation and give special feature events a stronger sense of impact.

Two other slots worth a look are Invaders Blitz by Light & Wonder and Bizarre by Nolimit City.

The Bottom Line

Dr Zappo gets most of its strength from the EyeBall mechanic, where ricochets create Wilds and multipliers that can rise to substantial values. Energy Fields add further potential, and the three bonus rounds gradually increase the power of each EyeBall. No-Brainer and Hidden Epic stand out due to their dual-direction shots, although the feature set offers little novelty for anyone who knows Jaws of Justice. FeatureSpins and 2 Bonus Buy choices provide alternative routes to the main extras, but originality remains the main weakness.