Lightning Aura's upgrade seems to be a waste. It's already a 2-cost card, thus the draw power has a little chance to be useful. I would suggest instead either adding another lightning orb or increases the defense gained per orb by 1. Probably the latter since additional orbs also means increased offensive power for what appears to be an defensive card.

I also just found that Robotic Walls appears to either not have an upgrade or it doesn't say what it does upgraded. If it doesn't have an upgrade, I suggest either making it 0-cost or innate.

Robotic Walls is a mistake on my part, forgot to update the text when I changed the card. It will be fixed soon :)
Your argument on Lightning Aura's draw makes sense so I'll change that upgrade too. It used to upgrade to 3 orbs but I find that way too strong for a 2 cost common...

Thanks for the feedback !!