There is some clipping in the cashing sound effect. I hear it all the time, so it bothers me some. Maybe it has to do with how the engine handles stopping looping sounds? If so, you could maybe loop the sound manually in some editor and play the while thing once in the engine. All in all the SFX are very sharp and loud. Some volume controls would have been good.
I like it that there are instructions within the game, makes it easy to play.
It's a cool game idea. I think the setting (background, icons and ambient sounds) fits the story well.
I think there is maybe some lack of meaningful choices, which is kind of the case in general for slot machines I realize while typing :D
Impressive submission anyway, it's very cool when people come up with these, for me at least, unfamiliar types of games during jams!