Ok, a few comments:
1. Your resource gathering/economics system was fine - villagers and pharoah were all put to good use and in decent numbers - not a problem there.
2. Domination of the sea was good, though it tok you a wee while to destroy his shipyards - even after it was obvious that he had nothing to stop you doing so. However once you had found and destroyed his shipyards, your leviathons practically did nothing for the rest of the game - you could have disbanded your transport ships to free up pop slots, used 1-2 of the leviathons for transport instead, left one guarding that spot the ai insisted on trying to build shipyards at, and had the other patrolling the coastline to check for other harbours popping up/enemy troop movements (and if the AI did try to build another shipyard, you could easily have all 4 leviathons immediatley go after it).
3. You didnt touch the two relics on your island - both of them improved your military units somewhat, so there was no real need to get them early on, but later in the game when you were sending troops over to attack, you could easily have sent your pharoah to grab them. After all your economy was in good shape by then and you shouldnt turn your nose up at free improvements.
5. God powers - you used the first 3 pretty well, but your meteor strike was a waste. Admittedly it did a fair amount of damage - taking out a market place, temple, armory(I think) a coupla houses and quite a few troops. However you failed to follow it up with an attack - instead giving the AI a good 3-4 minutes to train more troops, build another 2 temples, houses and repair most of the splash damage done. Plus there was a much juicier target for your meteor strike - just below the AIs centre town centre was his main unit production centre - 2 barracks, 2 Archeries, 2 Stables all tightly packed together with his TC and a lot of his troops in the surrounding area. If you targeted the meteor strike here, you could have done huge amounts of damage.
Ideally you should have waited until your troops were on the island before hitting them with meteors, and then followed up with an attack to finish off any surviving buildings/troops. You could quite easily have sent a fast moving unit in to scout for best spot to hit beforehand and to draw enemy troops to the target spot.
4. This ones the biggie... Your tactics, frankly, sucked. They basically consisted of filling up 2 transports with as many troops as you could and sending them over to the island, unloading and then just attacking willy nilly. You should really be using the army groupings so you can select different unit types at the touch of a key (ie group 1 for heros/priests, group 2 for slingers/ranged units, group 2 infantry/myth units, group 4 siege weaps) This way you can quickly select group 4 to attack buildings, group 1 to target myth units, group2 to attack his heros, group3 to take on everything else.
You should be prioritising attacking the AIs heros with your archers because they were doing the most damage it seemed. (Likewise the AI was obviously always going for your priests first - thus the few myth units he had were stomping you - you need to protect your priests and use more of them)
Also - you were landing your troops at the exact same spot on the island every time - The AI obviously wised up to this and had his army massed on the coast at this exact point after the first couple of attacks (they weren't patrolling the coastline). Thus your army was coming under attack as soon as they were unloaded off the ships.both the north and southern edges of the island were undefended, and you could easily have slipped in there - south particularly because that was close to his barracks/TC et all - could have done a lot of damage there.
So, re. your statement that the Greeks are unbeatable - you had them on the ropes after your fist couple of attacks, but you didnt press your advantage, and didnt vary your tactics (trying different units isnt new tactics!), and the AI was obviously taking advantage of this fact (It was hard setting after all) - it had archers taking care of your priests, heros wiping out your myth units, and his cavalry, infantry, and the odd myth unit taking care of the rest.