Gem Heat Slot by Playtech

Most fruit-machine throwbacks hand you one bet and one set of reels. This one adds a purple HI ROLLER button that lets you stake ten or twenty times the normal bet, and in exchange upgraded 777s go onto the reels from the first spin instead of waiting on a bonus. The x20 setting is the one carrying the roughly 5,000x ceiling. Play the standard bet and the top end sits far lower, so the big number and the higher stake are tied together.

The upgrade idea runs through everything. Red, green and blue 7s arrive stacked two and three high on every reel, and lining those columns up is where the base game earns most of its keep. The three colors aren't equal, though. Red pays best, green sits under it, blue is the lowest of the trio. In the Free Games that pecking order gets rewritten: lower 7s are promoted to higher-value ones, so a screen of blues can cash out like reds. Three of the flaming blue FREE GAMES diamonds anywhere start that round, and it runs ten spins.

The blue GEM HEAT logo is the wild, standing in for the paying symbols and paying the most itself when it lines up. Everything glows against a dark red background inside a red neon border, with flames curling up the left and right edges. The reels mix glossy casino staples: gold BAR, BAR BAR and BAR BAR BAR tiles, a gold dollar sign, a stacked pile of gold bars, a star-studded horseshoe and a sparkling blue diamond, all sitting on black reel strips. It's a Vegas parlor slot with the flame turned up.