Whereabouts are these free passages? I don't know if I entirely know what you mean.
There is no "free" passage on your screenshots, so not to replay the game I sketched what I mean. On the picture above, if there was no blocks on the right (which I erased with pink) then it will be confusing. And it happens in some rooms/screens.
The colour of the player indicates how much health you have, if you die immediately it will be because you were already nearly dead and you got hit one last time. If you were the original bright blue colour when you died then that would be a bug that somehow slipped through.
I died a couple times almost immediately without previous hits. I think maybe it collided with enemy several times somehow and received multiple damaged.