I am having a difficult time remembering this one old series that I watched on Netflix kids when I first tried Netflix.
I remember that the title was around Xero since I remember that I thought that the title was Near Zero.
Some of the characters was this alien girl that looks like a human, female, teenager that has a backpack with her 24/7. This backpack is a armored lizard (That can stand on two of its feet) that need to be with her to recharge. I recall that there was a portal in the boiler room from a school (With no one in it usually) that allowed her to go into this dimension. These two boys, what their name is, I can't recall, followed her, if I remember correctly, and they went into the dimension.
In the real world, it was live action but in the dimension, it was a video game style. When a person went into the dimension, they got armor and a weapon. The two boys found the alien girl (that looks like a teenage girl) crouching down doing something (looking for the boss?) with the tech lizard right by her.
I remember that they went to a new level after season 1, where, if my memory serves me right, where they lost one of the boys that later appears as a orb of light that helps them occasionally (but not fighting).