Very nice! The quality on the goro thumbnail isn't very good though. I suggest you add a bg to Goro's head too, just to match Ermac. And some names would be nice too. But anyway, I really like the dark effect, and the Ermac is rather cool too. Nice work!
Well this is pretty interesting looking. You did a nice job with the silhouettes, the lighting effects are basically perfect in my opinion. I agree that names would be good, and give Goro's mugshot a BG so it looks good against Ermac's. Also, these seem a little big, perhaps they need to be shrunk down a little to fit better into the pic.
The background itself is pretty solid, I really like the effect the the cloud and moon. Though, it looks maybe a bit too simple in some areas, it was all goes together quite nicely. Also, great looking shadows by the way. Just an experiment, but I think it looks pretty solid and original.