I agree with Trquangss, Fred would be a lot more "expressive" with more animations (simple and schematic animations, it suits perfectly the pixel graphic).
I agree also about the secret areas, it is a game that should be impronted to exploration (it somehow reminds me of the 8bit era game "Dynamite Dan", never heard of it?).
What about a device to swim and another to fly, only for a short time and in certain levels?
Cheers