I like the cute little ghost's animations. The ideas for using the crystals to complete the levels and the dialog with the NPCs are good. The platforming feels a bit slippery and the air movement makes some jumps a bit tricky. The camera also gave some trouble in some levels as it was hard to see what was ahead of you or below you in some areas. The crystals should probably be multi use rather than single use, as they were not obvious how to use each one of them and having to restart the level after spending your only crystal and being stuck in a hole was a bit frustrating. Some nice ideas here though that could definitely be refined. Nice work!