I played this game for the first time last night (my first board rpg actually) and was a little confused by the stand up and revive concept upon reading the rules this morning. What is the point of standing up? Is this just what you do when there are no other hero adjacent to you? Standing up is the only action you can do, but when you are revived are you actually allowed to perform actions that turn?

Exactly. Revive results in more actions. Every hero gets 2 actions, correct? If someone revives a fallen hero, it costs one action, leaving the second action to, say, attack a monster who's been knocking the heroes down. In addition, the revived hero will now be able to act twice as well on his turn. If a hero isn't revived, he can use stand up, which is the only action he can take that turn, therefore costing the hero group two actions to get him up, instead of just one. It could also leave him still in harms way to get knocked down a second time.

Great, it wasn't something complicated at all. Thanks for the affirmation.