This walkthrough will get you all of the pickups and secrets. It will not get you all of the enemy kills, there are several bats I passed up. In order to unlock them you just have to run around and hit the proper tiles to trigger them.

If you follow this you will also get the following achievements
You are Really Loki
Thor's Mercy
I am No Heracles
Dionuysius Wisdom (If you only get hit by ONE sword)

In order to get the So Salacia achievement just wait in Neptures room right before surfacing until your last breath. In order to get the Exaggerated Threat achievement just walk around very carefully and make all of the swords fall.