1. The sword of olympus is useless without a god putting its powers into it... that is the impressions i got during the 2nd game... zeus put all his powers into it and used it to defeat the titans... kratos put all his powers into it at the start of the 2nd game... now it may be that since kratos is a fallen god, he can't properly take the power back and thus can only use it in spurts... but that is just my guess.. its would suck to use it all the time, gameplay wise...
2. They allowed him to open it because zeus favored kratos above most other of his demi-god children and he favored athena the most among his godly children (since she is a part of him and was created by him without a female's womb). Ares was attacking her city and since they couldn't start a war among the god's (look at what kratos ended up doing!!) they had to resort to a 3rd-party getting the job done... and it was the only way... i think they didn't understand the scale of evil inside it, so they weren't as afraid.
3. Athena mentions that she exists on a higher plane now... and is only able to objectively view the world... unlike before where the love for zeus clouded her judgement (the first encounter in hades)... so she is not the same athena that died... he motives and personality have changed. for better or for worse is up to you to decide.
4. The box still contained the power to kill a god of any power... kratos returned that power after killing ares... he didn't retain it... he was made a god after he tried to kill himself... zeus put back all the evil that was released and athena fearing the worst if it was released, secretly put into it hope... zeus didn't know about the hope part... that stayed with kratos... he put the powers back into it, but the seed of fear and anger had already grown in his heart... i don't understand why the second opening did nothing but it may have something to do with kratos not really wanting the power (he tried to stop pandora).... or that it was a one time use thing.
5. He vowed that if "all of olympus will deny me my revenge... then all of olympus will die"... she didn't deny him anything... she sexed him up and told him what to do... she aided him... he is not that much of a punk lol... same thing with the smith god, he only ended up killing him after he tried to get in his way. so memo is... don't get in kratos' way.
6. no, that was another dude, in gow3, he is made of lots of rocks... kinda like "the thing" from the fantastic four.... kronos was defeated before zeus used the blade. and he was wandering tartarus because zeus banished him there after kratos ended up getting pandora's box... he was pissed off and went nuts.







