I enjoyed this one quite a bit. The islands were detailed, especially given the time frame. The astro cam was a nice touch and I thought the jetpack was neat, though it did get me in trouble a couple times.
I agree that a checkpoint at each level would be much more enjoyable in this setting. I also thought the teleport was a bit unnecessary, but overall I loved the concept and if you worked on it I would be excited to check it out more. Great job!