.....Really, from what I've seen, no one has unlocked all the characters we've seen previously available in the game in trailers and screenshots. There have been Character select portraits of the king, the Undead-summoning Knight, and the Mage Knights. Now, those guys COULD be downloadable content in the future... But I still don't think we have everything figured out yet. It's too early to be calling foul on Alien Hominid unlocking.
It's very intriguing, to say the least. This much content in an arcade- No, in ANY game, now-a-days, is a much welcome throwback to the old days.
Also, I think it'd be a good idea to make a list of "the additional unmentioned info" that this game has. Such as the difference in magic between similiar characters, the effects of the various effects, all that fun stuff.
Example: You can aim where you throw enemies, by holding a different direction after grabbing on. (Normal or Beefy mode, I believe.) Throwing enemies straight up is a great way to begin aerial rave combos XD Also, if you really skilled, you can run under an upthrown enemy, and throw him again!