I give it a 8...
... just because it's a preview. Elseway I'd give it more!
I think the final explosion scenes to be one of the best I ever saw here: you got the right solution to the probem by "stopping" it, because animating it would result in too much work for just few seconds of explosion!
But if you want some suggestions: 1) I would love to see Grenade Clock's guns to point to the things he's shooting at (the man in the lift doesn't even seem to be hit by bullets); and 2) while the sniper rifle scene doesn't need anymore work (the bullet passing through the body is made almost perfectly, I think you could add some blood lines when Grenade cuts Guard Clock's throat (or whatever it is), or else it relusts little too "fictious".
Thanks for listening to my humble advices! :-)