Lotto Madness Slot by Playtech

This one's old, and it plays like it. Lotto Madness dates back to 2006, so there's no grid engine, no tumbling reels, no collection meter, just five reels of numbered bingo balls bouncing against a bright red bubble background. Stacks of banded banknotes, a champagne bottle with two glasses, and a grinning blonde winner clutching cash and throwing a thumbs-up fill out the top of the paytable.

The Wild is a rolled-up "Wild card" scroll, and it does double duty. It stands in for every symbol except the Scatter and the Bonus, and it also pays as a symbol on its own. Two or more on a line return anywhere from 0.5x up to 500x, and a full screen of them is the biggest single payout the game holds. The Scatter, meanwhile, pays from anywhere on the reels with no line needed: three, four or five land 5x, 10x or 50x the total bet.

Free spins are the one moment of depth, and the trigger is narrow. You need a Bonus symbol on reel 1 and reel 5 at the same time, the two outermost reels. Before the round begins you spin a wheel that sets two things at once, the number of spins and a multiplier that's live from the very first one. The ceiling is 20 spins carrying up to a 10x multiplier. Land low on the wheel and the round is short and flat; catch the top and every win rides that boost the whole way through.

No jackpots, no buy button, no side bet. What sits on the reels is the entire game.