The Gameplay Experience: Testing the Mechanics
Symbols drop into a 5x5 grid with no fixed paylines, and three or more matching symbols touching horizontally or vertically clear for a win: land exactly three, and a wild spawns in the center of the cluster. The multiplier climbs by one with every consecutive drop on the same spin.
We tested Moon Princess over 500 spins on desktop at a $2 stake, tracking how often we managed to clear the entire grid, since that's the trigger for the game's main bonus round. Against Moon Princess 100, Play'n GO's own remake, the original's 5,000x ceiling felt noticeably more conservative, since the remake pushes the same core mechanic toward a 15,000x jackpot instead.
Book of Dead, which shares Play'n GO's house style of high-volatility grid design, resolves its own bonus trigger more predictably, but Moon Princess rewarded us with more frequent smaller cascades along the way.