Hi Elater!
Thanks for the feedback! I'm glad to hear you enjoyed the game! Did you manage to finish it?
Some tricks: To reach some parts of the map you have to use double jump. You can also jump from the top of the stairs, press up and z, you will feel some resistance to jump but it will go off the stairs.
The phase issues are due to the collision detection I chose to use... I'm thinking to address that in a future version of the game.