Navigate your character through an endless maze/puzzle using the directional arrows on your keyboard.
Collect the golden scales of Ouroboros because... we know you want them.
Avoid the oncoming lava from the left and the tail-eating snake from the right. Don't go too far and don't fall behind!
On the other hand, ice is still slippery so watch where you slide. There's no stopping on the ice.

Pick up power-ups to conquer obstacles:
Pales of water strong enough to put out lava.
Fins to help you swim through water that will otherwise slow you down.
Hammers to help you break brick walls.
Keep your eyes peeled for the ever-rare clock that can save you when your life's flashing by your eyes. Literally.

Use the spring boards wisely, though! They will launch you quite far and potentially into danger if you're not careful.

Good luck, Snake Runner!