I love me a nice platformer and this is a good one to manage in a week. I had some issues though. After I got the grappling hook, I died and then when I came back, the grappling hook wasn't on the platform, and I didn't have it either. So I was stuck. The wall jumps also seem to have a bit of an issue where you get half stuck in them, making things slow.
Graphics and sounds I really liked. Great job.