Even if you're absolutely not interested in this game or what's going on, this video captures Pekora's boasting and Noel's absolute legendary turn around of the points.
If you do know gambling, I don't, so I am sorry for butchering half the terms. I tried finding english equivalent for many words like Shimofuri chance, Gekiatsu, but it just felt like none of them could accurately describe what they actually were. The only one that's important is the Shimofuri chance, which I put as "free spin chance," because it allows you to spin a chain event and keep earning cash.
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I realized after rewatching this, it's pretty fast paced, so I'll explain a bit here too. Basically, Pekora and Noel are competing to see who can win the most points in an hour. At the beginning, Pekora takes the upper hand, as she scores quite a few Shimofuri, bonus, etc. (Also, Noel wasn't even playing until 10 mins in). Every time she wins something big, she'll turn on the mic and start annoying Noel by singing songs and bragging. Shirogane Noel then pulls of the clutch of the century and starts scoring big with 20 minutes left. At 10 minutes left, she has overtaken Pekora.
This game is quite different from regular slot machines. It also has skill in it, because you control a little character in the top screen by pulling the slots. Therefore it's not just random chance but has an element of game to it too.
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0:00 Noel, the worst poem author ever
1:09 game start
1:53 Pekora winning
4:54 start of Noel turnaround
7:18 results
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Sources:
• 【ドラクエ11S】ぺこらVSノエル マジスロ... pekora
• 【ドラクエ11S】今年もノエぺこ！！マジスロ... Noel