The Castle of Slotenstein (Evoplay): Frankenstein Hosts a Three-Booster Hold & Win
Published 16 October 2026. Evoplay launched The Castle of Slotenstein on 15 October, a Frankenstein-inspired Halloween slot built around a Hold & Win bonus game with three stackable boosters. Green Shock, Purple Trick and Blue Treat pumpkins change how the bonus develops, and filling the whole grid leads to a progressive Grand Reel of Fortune finale. Max win: 3,000x the bet.
Official press art: Evoplay.
Key facts
| Provider | Evoplay |
|---|---|
| Release date | 15 October 2026 |
| Game type | High-volatility video slot (5x3, 20 paylines) |
| RTP | 96.35% |
| Mechanics | Three-booster Hold & Win, Grand Reel of Fortune |
| Theme | Frankenstein, mad scientist’s castle |
| Max win | 3,000x |
Frankenstein, but make it boosters
The Castle of Slotenstein is the latest in Evoplay’s 2026 run of booster-mechanic seasonal slots, following its Oktoberfest and Asian-mythology titles. The setting is a mad scientist’s castle, and the hook is a Hold & Win bonus game fed by three coloured pumpkin Bonus symbols, each triggering a distinct booster when it lands on the reels.
Shock, Trick, Treat
Green Shock symbols raise the opening number of Bonus Game spins from three to four. Purple Trick symbols can drop extra Bonus symbols onto their reel or multiply existing Bonus values by up to 5x. Blue Treat symbols add their values to every Orange Bonus symbol on the grid. During the Bonus Game only Bonus symbols land, and every new one resets the spin counter, stretching the round and opening more chances to fill the grid.
Grand Reel of Fortune finale
Fill all five reels and the game moves to its progressive Grand Reel of Fortune finale, the target players chase through the whole feature. A Bonus Buy lets players skip the build-up and enter the Bonus Game with one, two or all three boosters active. Ivan Kravchuk, Evoplay’s CEO, said the three boosters each change the way the Bonus Game develops, calling it a suitably unpredictable addition to the portfolio just in time for scary season.