Thanks for the feedback!
Yes, the mini boss is located in the other reality and you have to switch realities in order to get to the final boss because the direct path to him is blocked in the initial reality. Beating the final boss will win the game.
That the enemies can hit you even though you are tiles away is actually a bug. The hit/miss/damage calculation when the impact is triggered by the animation uses the players initial position when the attack was initiated and not the current tile. Its really one line of code to fix that.
The smooth transition of the npc was on the todo list but did not make it in the build, same goes for the options and instant step movement.
Unfortunately I do not have a AMD GPU at my disposal to check the missing textures and surplus geometry you where seeing. Which build did you test, the WebGL or the native Windows build?