I'm a sucker for games-within-a-game and Farkle was a fun opportunity to learn a dice game I was not familiar with! For what you describe as a prototype, this feels quite complete for a game jam: there's bouts of increasing difficulty, and the interesting interaction between staking another roll of the dice to multiply the score or settling for safe bets. For constructive feedback, I'd say if you're looking to expand on the idea, think about how you can make the game put its own stamp on the mechanics beyond the established ones.
I like the atmosphere too. The Lynchian undertones were there: there's light jazz, red curtains, and a stilted aura of formality. I think it was probably best to resist the temptation to distract from finalising the polish of the gameplay loop to get this done, but there's plenty more that can be done to build on that tone. Just like in the Black Lodge in Twin Peaks, assembling familiar iconography without a reference point makes something feel a bit off in a satisfying way. I hope you can continue to work on this and carve out a unique take on this!