Go Gamble: This is a very high quality main menu theme. The bass and kick hit really hard and I love the jazzy organ overtop. The syncopated chord stabs hold an air of confidence that is really fitting of someone about to enter a casino to go gamble! I also really like the harmonic shift in the transition back to the beginning of the loop. I heard the button clicks and the sound effect and knew that meant the game was starting. Really unique idea!
At the Resort: Wow this track sounds so much like the de Blob 2 soundtrack. This track belongs in a game just like that. The colorful chord extensions give a flavor that sounds relaxing, but also mysterious, like there is something going on that is not completely clear. This is a very evocative theme!
Lost it All: The sad piano over the jazz organ and melancholy guitar fits the “bankrupt” theme of this track super well.
Constructive feedback: I don’t have much to comment on for the individual tracks. They are all quite high quality and seem game-ready for specific in-game situations. What I will say is that you should continue this OST and include more themes to fill out the entire game! Go Gamble is the one that sounds the most like it is in a casino, but I recognize it was your intent to have it as a main menu theme. If you added another theme that was the actual gambling gameplay, and then a final track that plays if you actually win, this would be a complete OST that could(/should) be turned into a real game.
Overall this is very high quality work that fits the theme very well and is ready to be implemented into a game. Excellent work and thank you for sharing!