Coin UP: Lightning starts on a three-by-three grid. Three symbols on an active line trigger re-spins, with new symbols resetting the counter. An extra row supplies Coin UP value upgrades and Multi UP multipliers, while a collect symbol gathers displayed values. Sticky coins in the base game remain until the bonus starts. The upper booster row is the key difference from a simple coin-locking slot without those upgrades.
To compare related slots formats, read the rules of Gold Express and Grab more Gold!.
The library also explains the difference between lines, ways and clusters to help put these mechanics in context.
Source: published game information.
