Ahhh, thanks to your hint I was finally able to beat it - wasn't actually that hard, I blame it on the late time of day :D But at the time I figured the hint from the princess out, I almost brute forced the solution by hitting shield-vases at random ^^ Played the other route too, the ending was kind of tragic.
I encountered two minor bugs: One time, I fell into a hole that kept sucking me in after respawning. The other time, I respawned with my blue, physical body in the mystic garden near the princess and thus had no way of coming back. No idea how I managed that though :D
Apart from that a really nice small game.