God Games - Why is Odysseus stuck?

So we go from Thunder Bringer to God Games but I dont see how Odysseus was stuck? He was the only one left but couldn't he still get away or was Zeus's power somehow keeping him to the island? I get Hermes comes down and helps him out but it looked like he already had a boat.

Also if Zeus was keeping him there why? In Thunder Bringer it seemed that Zeus 'respected' Odysseus as one king to another. Atleast no real reason to keep him there.