i really like it. Its kind of like a cross between games like Fishy and games like Snake. No major errors, but the normal score count increases its speed for a second when you pick up a coin. Try some powerups/more lives spawn. Get a bit more in-depth. This isn't too far from a lot of popular games.
You need to make it so that Memory Serpent can be cancelled if you accidentally click on it, and that if you cancel it when you can (after discard) you don't retain it and lose the card you sacrificed.