My major problem with it, well two actually, is that; One, the recoil they have after shooting is unrealistically large . And Two: you need to be a tighter editor, so many parts of most of your films, nothing is happening, you need to edit those parts shorter, like in this one where the guy pulls out the grenade, then about two second later throws it, that should be about half a second, or at least have some reason for him to hold it for so long, the it was laying at the snowtroopers feet for about a second, and they did nothing, I understand it was to match with the music, but they would have reacted. This is a problem I noticed many, many times throughout this film.
I give it a 3/5 mainly because of the second problem, and the major lack of story.