They work incredibly well. There is only one problem with it though, a bug that I should have predicted. If you are able to press the jump button at the exact moment you land on the spring, you'll end up doing a normal jump rather than using the spring.
Now that I think of it, I wonder if anyone would have discovered that if I hadn't had mentioned it. But, people have a way of finding these things out.
Now I move on to entities. After all, it just wouldn't be right if I didn't have random enemies walking around. Jumping on enemies is how you kill them in this game. That will probably make bosses pretty hard to design, though.