Roulette unlocks at player level 5.
You can spin the roulette every 8 hours for free, or instantly for an amount of gems that increases by 10 for each consecutive spin within the 8 hour timeframe.
(gem cost depends on player level). The roulette has 12 possibilities.
3 are coins , which amount increases at streaks 5, 50, 125, and 250, and also increases with the Player level (formula to be determined),
3 equipment, the level of which supposedly is 1-15 levels below the Player level (though as of february 2016 apparently bugged for player levels 41-50, giving the same results as player level 40),
2 rare resources, which amount or rarity (?) increases at streaks 35, 100, and 200,
1 extra spin(s),
1 gem, which amount increases at certain streaks and also by 5 at player levels 10, 20, 30, 40, 50 (to be verified),
1 key, which tier increases at player levels 10, 20, 30, 40, 50(?),
(oddly enough, the spin streak seems to indicate I should get better quality items, but on the wheel I can't see a (clear) color outline... )
streak 184 @ lvl 28
(gotten through extra spin) exact same possibilities as streak 183 @ lvl 28
streak 185 @ lvl 28
24k/48k/96k
20
1
1
1
2
2
3
1 /
streak 186 @ lvl 28
24k/48k/96k
20
1
1
1
2
1
3
2 /
lvlup to lvl 29
displayed items are still listed the same as at my streak 186, gold went up to 27k/54k/108k, so that's linked to level.
streak 187 @ lvl 29
27k/54k/108k
20
1
1
1
2
3
4
3
streak 188 @ lvl 29
27k/54k/108k
1
1, 1
2
3
2 (level 13)
4 (level 15)
1 / (level 20, chest)
(wait, what? no gems and 2 extra spins? only noticed that at the end of spinning, so might have been a visual glitch... gems were back for the second one after winning the extra spin)