I found another path/ending and the third place I tried led me back to the first path. I tried a no-death and no-kill run but could not succeed. You kill too easily, even when not trying. There's also several blind spots.
I may need a hint.
Drop down into the purple lava area (the first hole in the ground you encounter), then when you get to the snow area don't go into the first green pipe you encounter, keep going further ahead and you will find another green pipe which leads to an alternate ending. It's true the other ending is just to follow one of the other paths and be pacifist.