Did Guitar Hero World Tour kill my Xbox 360?

Fixing it depends on the problem, 2 red lights is indeed an overheating issue. I would recommend installing the game to your HDD to cut out the heat generated from a spinning disc, also consider standing the xbox up on its side and keep it well ventilated. If the game still doesn't work, then Neversoft are legally obliged to replace the game if it's a software issue, so ask for a replacement.