So when you beat the game, you unlock the level section option. To get the Are You A God? Achievement easier, you just need to play through the first two checkpoints (not really sure about playing the second checkpoint, but I did it just in case) and the final boss of the chapter. And continue into the next chapter like normal up until after the next second checkpoint and load up to the next boss fight, continue til you beat the game and get unlock the achievement. And you also get the tacky golden proton pack. Have Fun!