Hidden Slot by ELK Studios

Professor Taylor's Pyramid Hunt on a 5x4 Grid

Hidden puts you on a desert expedition with Professor Taylor and his nephew Benjamin, two characters chasing the lost golden topstones of the Great Pyramids. ELK Studios built this one around a 5x4 grid with 178 connecting paylines - not ways-to-win, not clusters, but a proprietary payline system that maps 178 distinct connecting paths across the reels. Symbols drop onto a transparent playing field as heavy stone and gold blocks instead of spinning on traditional reels.

The paytable splits into two tiers. High-value symbols include a golden Sphinx bust and Professor Taylor himself (both paying 10x for five-of-a-kind at base bet), plus a grinning camel and red-haired Benjamin. Card royals fill the lower end - K, Q, J, 10, A carved into sandstone tablets. The art style is detailed cartoon work with warm golden tones and blue sky behind the pyramids. It looked good in 2017, and it still holds up.

Flashback Respins - the Base Game Lifeline

Any spin in the base game triggers the Flashback Respins randomly. The background shifts to show ancient Egypt as it once was, and 1, 2, or 3 of the middle reels (positions 2, 3, 4) get covered with sticky wilds. You get 3 respins. Those wilds stay locked for all 3 spins.

Three full wild reels sitting in the middle of a 5x4 grid with 178 paylines is exactly as strong as it sounds. That setup forces wins on almost every connecting path. Even one sticky wild reel bumps your results - two or three shift the math entirely. The catch: additional wilds landing during Flashback Respins are regular, not sticky. And the feature won't retrigger within the same activation. Still, it carries the base game. Without it, the 24% hit frequency would feel thin.

Treasure Room Free Spins and Expanding Symbols

Three magnifying glass scatters on reels 2, 3, and 4 open the Treasure Room. You start with 5 free spins. Each additional scatter during the round adds 1 more spin.

Before the first spin, the game picks one random symbol from whatever landed on the triggering spin (excluding the magnifying glass). That symbol becomes the expanding symbol for the entire round. After each payout, every instance of the chosen symbol expands clockwise into a 2x2 block. All non-expanding symbols get cleared off the grid. The expanded blocks drop down, new symbols fill the gaps from above, and the result pays again. Then the next free spin starts.

The expanding mechanic is where the 2,150x max win lives. If the game selects one of the high-pay symbols - Sphinx or Professor Taylor - and they cluster well, those 2x2 blocks create dense winning formations across the 178 paths. Getting a low-pay symbol selected as the expander, though, limits the ceiling significantly. That randomness adds variance the medium volatility rating doesn't fully communicate.

The Numbers in Context

RTP sits at 96.3% with no operator-configurable tiers. One RTP, every casino. Hit frequency is 24%, so roughly one in four spins returns something. Bet range runs from 0.20 to 100.00 EUR.

The 2,150x max win is modest. For a 2017 release, it was fine - the industry standard sat much lower before the 50,000x arms race started. By current standards, high rollers betting 100 EUR per spin cap out at 215,000 EUR. There's no buy bonus option either, so reaching the Treasure Room requires patience and luck.

ELK Studios rated this medium volatility at 6/10 on their internal scale. The 24% hit frequency supports that - wins come often enough to sustain sessions, but most payouts are small. The Flashback Respins carry most of the base game weight, and the free spins round either delivers or disappoints based on which expanding symbol gets selected. That binary outcome makes individual sessions feel more volatile than the rating suggests.