Very nice! Polished, catchy, addictive. Pretty easy, though, if you play safe.
I love how the random chance is balanced out by raising the stakes as the round continues, so getting screwed by your first card doesn't hurt you that much.
Funnily enough, the first stage is hardest, because it doesn't have the 2x2 highlight hint. Once this hint unlocks in stage 2, you can semi-reliably rush it, getting 2-3 more cards risk-free, and getting a stake half the time. This makes it almost impossible to lose unless you get extremely unlucky right after buying into a new stage.
Still, super impressive work.