Continuity mistake: During the poker game, the Colonel says "I've got five aces" and he lies down his cards in front of him. You can see that next to the Colonel there is half a coin and a pack of playing cards. When Bugs says "I've got six aces, sir." he takes the half-coin away from the Colonel, but the Colonel's cards and the pack of playing cards have disappeared.
Continuity mistake: At the beginning of the poker game, you can see that the Colonel has his pistol between the chips when he asks Bugs, "How many chips, sir?" but when Bugs gives him a 100-dollar note, the pistol has disappeared.