Here’s an idea I had:
What if the entire arena were coated, at first, in metal? As the snake travels through the liquid metal it grows constantly. (There could be different colors that make the snake grow at different rates.) The player must pilot the snake from a start point to an end point without crashing. This could be made harder by obstacles. (For example something that the snake must loop around x times or a 'spike' that raises and lowers that splits your snake it two if you pass over it while raised.) Some could be more puzzle oriented than others so you could really dictate the pace of the game.
What if the entire arena were coated, at first, in metal? As the snake travels through the liquid metal it grows constantly. (There could be different colors that make the snake grow at different rates.) The player must pilot the snake from a start point to an end point without crashing. This could be made harder by obstacles. (For example something that the snake must loop around x times or a 'spike' that raises and lowers that splits your snake it two if you pass over it while raised.) Some could be more puzzle oriented than others so you could really dictate the pace of the game.