Puck.light values depend on how often it's called

Ultimately Espruino should provide enough of a wrapper around things that the majority of people don't hit these gotchas. Having to worry about flat batteries is a new thing for me (previously everything was regulated to 3.3v so pretty much either everything worked or it didn't).

At some point you're always going to hit low-level issues (you do with PCs too - it's just a lot further down the line!) - hopefully Espruino makes it less painful when you do hit them though... For instance using normal compiled code with the magnetometer you'd have very little idea of whether the whole thing had crashed or whether it was just the magnetometer.

I'll have a quick look at the light issue this morning - hopefully it'll be quite an easy fix.