Tidal Clock

5 reels × 3 rows, 243 ways, left to right. Winning symbols clear and new ones fall in; each cascade in a spin climbs 1× → 2× → 3× → 5×. Wilds land on the three middle reels.

The Mystery bubble lands like any other symbol, on any reel. Before wins are counted, every Mystery bubble in view turns into the same paying symbol, chosen by one draw weighted as the reels are: a premium symbol 25 times in 71, a low symbol the rest. It stays that symbol. About 66% of spins show at least one Mystery bubble, on the first drop or a later one.

3, 4 or 5 scatters on the first drop of a spin award 8, 12 or 16 free spins; 3, 4 or 5 on a free spin add that many again, up to 60 free spins in all. The feature can be bought for 8× the bet with 8 free spins, for 11.99× with 12, or for 15.99× with 16. Each price is what those spins return on average, less the house's share: no tier is a better buy than another.

Bought, the three return 96.49%, 96.48% and 96.47%, as measured (each give or take 0.18 points at most); most buys return less than they cost.

When two scatters are in view, the reels still turning stop more slowly. That is decided only by the reels that have already stopped and happens every time two are in view, whether a third comes or not: it says nothing about what the turning reels will show.

One spin, feature included, pays at most 7,500× the bet: a spin that reaches it stops there and is paid exactly that.

The return printed here was measured, not derived: 96.46%, give or take 0.09 points, over 60 million spins. 36.6% of spins pay something; the free spins come about one spin in 177 and pay 5% of the return.