40k Campaign?

[Nick]

I dont play 40k, but I have an idea, slightly out of the box, but see what you think. An audacious plan is being put together by the collective enemies of the Imperium. Rumours have it that they are engineering portals (Stargates?) in order to travel back in time and destroy the human race on their home planet earth ( Star trek First Contact?).
In brief, 3 battles, each one Space Marines v any alien army. The Space marine objective is to destroy the portal before it can be activated. the Alien objective is to finish the portal and get as many troops through it as possible.
Once each battle has been completed, the action moves to earth 1944. ( Guess you can see where I'm going, Vince!) there they will face a WW2 Army, the outcome of which decides mans future fate!! what do you all think?

WW2 rifles would be what, Str 2 AP -...........pretty sure even my Dark Eldar would be able to survive mass volleys of that out in the open lol......