Cascade cycle
Step 1: normal spin, wins are evaluated. Step 2: winning symbols "pop" and are removed. Step 3: symbols above shift down, new ones drop in from the top. Step 4: evaluation again. The cycle continues as long as each step results in a win.
Each step of the cascade is essentially a free re-spin within a single bet. That’s exactly why players love this mechanic: one spin feels like a mini-series.
Multiplier Ladder
Most often, cascades are enhanced by a progressive multiplier: the first win ×1, the second ×2, the third ×3, and so on up the ladder. A long chain turns a modest starting combination into a big win.
The multiplier and ladder length are the main levers of volatility in the cascade theme. They are selected so that the total RTP stays within the target range.
Clusters — a related mechanic
A closely related format is cluster pays: winnings are awarded not for a payline, but for a connected group of identical symbols (horizontally/vertically). The cluster bursts, and new symbols fall from above — the same cascades, but in a "field" geometry. In our engine, both mechanics run on the same cascade renderer.