With thanks to Kerry Muste (@KerryMuste), this looks just the ticket as a step-up from Lightbot. I've not done this with my 8 y.o. yet and I've only spent 15 minutes on it myself (I'm supposedly at work :)). That was enough time to kill precisely one ogre.
What MIT's Scratch does so well is simplify the interface by wrapping the code in a drag and drop format. That is great but it's aims are larger in that you design the game from the outset.
In Codecombat you are, well, coding the combat, at least initially. It gets you writing code straight out of the gate.
this.attack (etc) ... I loved it and I really shouldn't.