One of Jigsaw's saving graces as a human being is that he generally gives his victims some sort of fighting chance, though the opportunity for survival is squandered needlessly by so many.

Obi (Tim Burd) gets a message from Jigsaw but fails to read between the lines; if he'd have analysed the subtext he would've known how to switch off the furnace that burns him to death.

How Easy Is It To Achieve? So-so. Just make sure you listen carefully to your tape, especially for any particular words that are stressed or over-emphasised.

If You Really Can't: Then you should probably start reading logic puzzle magazines for practice.