Gregor Samsa was a cockroach when he woke up one morning.
As Gregor Samsa awoke one morning from uneasy dreams he found himself transformed in his bed into a gigantic insect.
Same idea, but a world of difference. Read them out loud. (Go ahead -- nobody's listening.) Can you feel it? Can you hear it? The first sentence is awkward on the tongue. It lacks rhythm. It sounds funny. It's not very detailed. There's less intrigue. The first sentence has the ring of an amateur.