In games like this, when a player has to deal with many lies, s/he must have some foundation, some statements/facts that s/he knows to be true. Without such foundation a player will be lost. In your game such foundation are words of the narrator (words floating in the air) and experience of the player (empirical experience about doors). Ideally a player should be able to complete game without trying to make a lucky guesses.
Now return to the narrator. The words of the narrator give the player information about rules of the game and about features of stages.
Unfortunately, the narrator doesn't always make its job correctly.
1.It is NOT always clear if what the narrator says applies only to particular stage or that there happened change in the rules.
2.On the stage 4 there is door that says "This door doesn't lead to life". It presents paradox, because on one hand if it's lying then it would violate words of the narrator that the life door is honest. But on the other hand, if it's true then then it would violate words of narrator from stage 3 that a honest door leads to life. I had to resort to testing and I discovered that the door tells the truth, it leads to death. So rules were changed, now honest doors can lead to death and a player can't figure it out without trying to pass the door.
3.On stage 5 we can see two doors (actually three, but it's easy to see that the third one is a liar), gree one with text "I lead to life" and blue one with text "I have cube above me". There are no reasons to chose one over another. Yes, we know for sure that the the blue one is honest, but as we already saw honest doors can kill too. And only testing shows us that we must choose the green door.
4.On the stage 7 we have two candidates for a life door (other are either liar or don't lead to life anyway), red "Blue and sphere are dishonest" and green "The door that leads to life isn't yellow". There is no way to know which one of them leads to life. Even more, testing shown that neither leads to life, instead the green door with a cube over it and text "Nothing with cube leads to life" leads to life. The blue door warned us about it, but we didn't have any reasons to believe it. Again, there was change in rules (namely that liars can lead to life) and a player has no idea.