Love where this is going.
The main char has a red space suit, can only take me back to Rad Gravity on the NES

The top roof and the background blends together damn good, perhaps too well. IE add some separator to show that that's is roof, and that's something your hero will collide with.
As everyone else says, the alien maybe needs some more detail.
Maybe the main char should have his face a bit more stuck into the helmet. I mean he doesn't have a vulture's neck, right? Maybe I'm too hung up on this and if you stick his face in the helmet more maybe it'll remove some character. I dunno. The face looks more okay in the still than in the animation.

Here's one space suit: http://www.ketzer.com/original_movie_props/bruce_willis_space_suit.html
here's another: http://www.luxurylaunches.com/entry_images/1108/05/space-suit.jpg
Not that any of those define how the best/coolest looking one should be. But incase you hadn't seen them.

I really like the portraits! The frames for the portraits are way too thick making it hard to see the actual portrait because the frames are taking too much of my attention. but that's maybe just how I feel.

Have you seen the game Rudra No Hihou? Rudora's Secret Treasure?
If not I suggest you take a look at it. It uses some cool ways to animate characters and monsters.
Have a look: http://www.youtube.com/watch?v=3XsrjWWCQN0

They separate parts of the body and move them separetly from the rest. It's a pretty simple way to do things.
Maybe you can make use of what's shown in the video?

here's an image from SotN, if is an abbrevation of Symphony of the Night:

Not sure what SotN style doesn't allow which you are doing. But here's my crits:
* it looks like you've accidently clipped his right side. it's a straight like down and then suddenly a knee sticks forth. is it supposed to be so?
* does he only have one arm?
* I don't really see what the part on his stomach, what's it supposed to be? a belt?
* maybe you can make the character slightly broader?

I dont' see any picture