Loved it! It was quite easy since I spent hours in snakebird in the past; so I had the basics.
I know I'm a bit late to the party but I'm sure you can make it to a full game if you still want to.
Look at Snakebird if you haven't (OK I'm pretty sure you did already :D) and give more content based on their challenges? I can see spikes, water (maybe that do not kill you but forces you to swim to another place?), portals of teleportation, rotted fruits that remove 1 from your size, fans that pushes you side ways etc.
I'm terrible with level design, but I'm sure this base is enough to propose several "pits/levels" to the player with each having the overall same pace than the one you designed already.