Very nice!
I got up to level C-5 on another computer while traveling, but that level absolutely escaped me.
Writing this on my home PC, The only thing I can think of that I didn't try (and can't get back to without playing all through again :( ), is to walk into the spikes (taking damage), then plant the sigil and turn back, hoping that teleporting into the sigil would not cause taking damage again, and then I could leap past the second spike. But not quite sure.
In any case, absolutely enjoyed this title. Very well done! It is a great example study of how a simple puzzle game makes or breaks 100% by how good its level design is. If the puzzles don't have variety, then the graphics and music and polish alone would not be able to keep it interesting for long.