Well, your friend certainly is a very lucky! I commend you on the brilliance of the piece!
Vision: the colours are vibrant, it isn't splodgy and the little shines are very very pretty. However, if I did have to pick some holes, I'd say that the little heart looks a little bit out of place and maybe if you added some darker shades to parts of the face, it could add some depth (for instance shadows under the hair). I love the writing, I'm not sure why. I just do,
Originality: we'll, I've seen Samus before, however I've never seen her appear in a christmas card, and itcertainly worked well.
Technique: the paint strokes are beautiful. The darker orange blends excellently into the lighter orange. The monster (Grr I can't remember what it's called ) is excellently done with its weird veins and is definitely how I remember them. There is sme slight bleeding of red paint into grey on the chest plate, but that isn't particularly noticeable so it doesn't matter too much.
Impact. The blue behind her, contrasting with her light skin, blonde hair and orange armour is reallllllly nice. It's bright and vibrant, and pleasing to the eye. Much is the same with the black green and red on the other side.
All in all, to sum up in one word... Awesome.
I feel very awkward critiquing this piece, because it is so much better than any of my own works, but here I am all the same :3