It is very "red". Some images can make use of the range of a single hue but I don't think this is one of them.
I like the detail of the sword and the effects where it is thrust into the ground.
There is about 1/3 of negative space above the main character where the sky halos the kneeling man, but it is almost too symetrical.
And it is terribly hard to distinguish the background, middle ground and foreground. I find your light source obscure because of the lack of highlights and shading.
Also, a Valkyrie is most always a female warrior who carries a fallen Norse warrior, who has died with honor, to Valhalla.
Overall, the painting is really nice. Keep going, it has lots of promise.
"Creativity emerges only when the imagination is given the freedom it deserves."