The hammer

Mission 4: The Hammer
Armies

Space marines (Blood angels, space wolfs, etc):  2000 points*
Tyranids: 2000 points*

Deployment: Standard board size, no terrain.
Standard deployment, both sides rolling off to see who deploys and then goes first. Initiative may be stolen on a 6.


Objectives and game length:
Game lasts 5-7 turns, using random game length
At the end of the game, calculate the points values of all units that were completely destroyed for each side, adding an additional 100 for the warlord and any unique characters. (If the warlord is a unique character, only add the 100 once). Which ever side has the least points wins. **

Special rules:
If Space Marines won mission 3, they gain one Artillery Blast per Mission 3 objective that survived. Artillery Blast uses the following profile: Str 7, Ap 1, Large Blast
If Tyranids won mission 3, then they may select one tyranid unit per Mission 3 objective that was killed, except for the warlord.. When that unit is destroyed, it may instead be placed into reserves to return next game turn. (Space Marines will still get the points for it's destruction, and if it is destroyed again it will count twice.)
In the event of a tie, both sides gain victory benefits.

Narrative:

The battle for the planet draws to a close before long. With all the civilians either dead or evacuated, the Space Marines draw back to an area with less cover, forcing the tyranid swarms to march across a barren land of weapons fire. Depending on how the battle has been going so far, the space marines may find support in artillery barrages from afar, or they may feel overwhelmed by the sheer number of tyranids, seeming as if each brood slain simply came back to life! Regardless, both side will not give up easily- this is the final battle to determine whether the Imperium will be able to hold the planet, or if it will fall to the Great Devourer.

*Alternatively, seeing as this is the end of the campaign (designed so that it could be wrapped up in a long weekend at most), it's quiet reasonable to up the points value up to apocalyptic proportions. If you and your opponent agree, it would be a great way to end the battle.

** Also alternatively, if you and your opponent are the types who think the last battle should be to the last man, then forget game length and points value- play until every model is removed from the board! Either one of these will likely increase the length of the game, but if it's fun, then that's good, right?

Victory benefits:
If Space Marines win, they may walk away knowing that a faithful sector of the Imperium has been saved this day, and a lethal branch of Xenos scum have been wiped from the galaxy.
If Tyranids win, they may laugh maniacally as yet another world falls to the Great Devourer, as countless have before and countless will still in the future. With that planet's defenses gone, they will push on into the rest of the sector, wiping the planets clean of all biomass.