I played a four-player game recently, with 2500 points of Tyranids on one side, facing off against 2500 points of combined Space Marines (of the Black Templars chapter) and Space Wolves. I controlled half of the Tyranid army. We used the Battle Missions book to determine an army-specific scenario to play. The result was the Infestation mission.
Representing the late stages of a Tyranid invasion, the deployment had the defending Space Marines deploying in one corner, and the Tyranids deploying anywhere else. The entire defending army would benefit from the Preferred Enemy special rule, representing them having gotten really good at fighting Tyranids by this point. This would really help them out. The entire Tyranid army would get +1 to any cover saves, representing their adapting to the local terrain. Also, all area terrain counted as Dangerous Terrain, because the Tyranid attempts to strip the planet had started resulting in earthquakes, lava flows, and in this case poisonous/acidic water. Random game length would be used, and the side with the most kill points would be the victor.
Here are pictures of the initial deployment of both armies. As you can see, the Space Wolves have painted their armor completely black, presumably to fit in better with the Black Templars.
The small Northwestern continent of Imperial World 18-D93 was by now almost completely overrun by Tyranids from a splinter fleet of Hive Fleet Hive Fleet Behemoth. The original invasion of the planet has been for the very specific goal of recovering some Tyranid genetic samples from an Imperial lab. Since achieving that goal, the invasion continued to progress nearly unchecked as the Tyranid army swept relentlessly across the continent.
As it turns out, for some unknown reason, the world known as 18-D93 was of much greater importance than anyone could have guessed. The Tyranids had already defeated a combined force of Ultramarines and Space Wolves sent to stop it. Now a detachment of Black Templars space marines had shown up to join the remnants of the Space Wolves force. To warrant such a significant expenditure of forces, the planet must be of vital importance to the Imperium.
On the Northwestern continent, by this time only one remote outpost remained in Imperial control. At the outpost, the few surviving political dignitaries and military forces that had managed to find their way there were being hastily evacuated to another continent. In the wilderness around the outpost, small forces of Space Wolves and Black Templars deployed to delay the Tyranid attack on the outpost as long as possible, to allow the evacuations to continue. I assume there were also some Ultramarines deployed around the outpost, but conveniently on the side that didn't end up being attacked by Tyranids.
As the loyal Space Marines prepare to sell their lives dearly to buy time for the evacuation, the continent itself seems to be faltering. The effects of the Tyranid stripping of the continent's bio-mass, and the construction of the huge capillary towers used to transport the mass to the Tyranid ships in orbit, are being felt all over the landmass. Earthquakes are constant, and lava flows from the depths of the planet have caused pools of boiling acid to gush up through the surface. This upheaval has made the entire continent a perious deathtrap. Unconcerned, the marines defending the outpost spot the swiftly advancing alien horde, which seems to be on them in an instant. Knowing they will die regardless of the outcome, the marines determine the hurl themselves at the enemy and fight them with unbridled ferocity, headless of their own safety.
Tyranid Turn 1
The entire Tyranid force surged towards the nearly surrounded marines. In the excitement, the Hive Tyrant managed to be wounded by the psychic backlash caused by attempting to stretch his psychic abilities just a little too far. The three Zoanthropes on the Tyranid left side had no such problem, as they moved forward and destroyed the menacing Black Templar Land Raider with their Warp Lances. A unit of 20 Hormagaunts sprinted forward at full speed to charge the nearest Space Wolves. Unfortunately, they only managed to kill a few while having their unit nearly wiped out in return. The Space Marines were fighting with particular ferocity this day.
Space Marine Turn 1
The Space Marine right flank surged forwards and opened fired, killing one Zoanthrope and wounding the Carnifex. On the Space Marine left, the advance was a little more subdued. Both units in the Black Templar Rhinos disembarked. One Rhino sped forwards at full speed to plug a gap and block the Tyranid advance, but the other rhino had been immobilized by fire from the Hive Tyrant's Heavy Venom Cannon. Fire from the two Dreadnaughts and the Long Fangs mowed down some in the advancing horde, but the effect was hardly noticeable amidst the swarming advance of the Tyranids. They did, however, manage to kill one of the Hive Tyrant's Tyrant Guard.
Back on the Space Marine right, the unit of Space Wolves led by their commander easily finished off the Hormagaunts that had charged them. I appears as though another unit of Space Wolves had charged the Carnifex, but it was then determined that they had fired rapid fire weapons, and were therefore not allowed to assault.
Tyranid Turn 2
On the Tyranid left, everything surged forward. The Genestealers with Scything Talons ran out from behind the large rocks towards the Black Templars who had been in the Land raider, and were led by a chaplain. At the same time, Warp Blasts from the Zoanthropes killed several of the nearby Space Wolves and caused the survivors to fall back in the face of the devastating psychic attack. Meanwhile, The Carnifex, Hive Tyrant, another unit of Genestealers, and another unit of Hormaguants, these with Toxin Sacks and Adrenal glands, all advanced towards the two units of Space Wolves in their path.
On the other side of the battlefield, the remaining unit of Genestealers charged into the front of the undamaged rhino, which despite their efforts remained undamaged. The rest of the Tyranids on the right flank had to make their way around the large rocks jutting from the ground, but the bounding Hormagaunts and Carnifex managed to reach and assault the closet unit of Black Templars. Several were killed on each side, but the fighting was inconclusive and would continue.
Back on the left side of the Tyranid onslaught, the Genestealers charged the Black Templar unit with the Chaplain, but only killed a few. The Carnifex and Hormagaunts charged the Space Wolf unit with the Wolf Priest. Unfortunately, the ponderous Carnifex was brought down before it even had a chance to strike a blow. The Homragaunts, however, managed to kill several of the marines. At the same time, the Hive Tyrant and remaining Genestealers attacked the unit of Space Wolves that had been depleted by the earlier Hormaguant attack, and the combined assault finished them off easily, though several of the Genestealers were lost.
Space Marine Turn 2
A torrent of fire opened up on the Space Marine right. Long Fangs split their fire, killing several Genestealers and pouring the rest of the fire at the exposed Hive Tyrant. Out in the open after it's successful assault, the Hive Tyrant and his Guard took fire from the Long Fangs and two Dreadnaughts. The weight of fire killed the remaining Tyrant Guard, and left the Hive Tyrant badly wounded, with only a single wound remaining. The Assault Cannon Dreadnaught then assaulted the beleaguered Hive Tyrant, but the Tyrant ripped the close combat arm off the machine before it had a chance to strike, and he managed to survive the Dreadnaught's resulting attempts to kick him to death.
At the same time, the broken unit of Space Wolves continued to fall back, but the nearby Black Templars finished off the Scything Talon Genestealers and consolidated towards the Hormagaunts, who by this time had finished off all of the Space Wolves they were fighting except for the Wolf Priest. On the Tyranid right, the battle continued between the Black Templars unit and the attacking Carnifex and Hormagaunts, who managed to nearly finish off the marines, leaving only two still standing.
Tyranid Turn 3
The Tyranids continued to push forward and close the noose on the Marines. The remaining Genestealers on the left charged the Long Fangs, but only killed one before they were finished off. The Hormagaunts finished off the Wolf Priest, and the Hive Tyrand tore apart the Black Templars Dreadnaught, before consolidating behind some large rocks for cover.
On the right, the Zoanthropes destroyed a Rhino with their Warp Lances while the Hormagaunts and Carnifex finished off the unit of Black Templars. In the back, a unit of Tyranid Warriors led by a Tyranid Prime observe the course of the battle, ready to reinforce wherever needed.
Space Marine Turn 3
On the Space Marine right flank, the broken unit of Space Wolves finally rallied when they saw a unit of Black Templar scouts arriving from reserve. They couldn't very well flee from something that Black Templar scouts were advancing towards. The Black Templar Chaplain and his remaining escort advanced towards and fired on the Hormagaunts. Meanwhile, despite his attempts to take cover, the Hive Tyrant was finally gunned down by the other Black Templar Dreadnaught, avenging the destruction of his former colleague.
The Black Templar Chaplain and his three reamaining men bravely charged into the mass of Hormagaunts and, fighting with desperate rage, slaughtered them all.
Tyranid Turn 4
The relentless Tyranid advance continued with renewed vigour, however, as they still had plenty of units to commit to the battle. On the right, the Hormagaunts leapt forward to fall on the few survivors of a Black Templar unit who had been conducting a fighting withdrawl. Nearby, the Genestealers ran all out to assault the Long Fangs. They only dragged down one of the tenacious old warriors, but they continued the fight. THe Carnifex on the right managed to sneak up behind the equally ponderous Dreadnaught, but only managed to slightly damage it while taking a wound in return. The rest of the Tyranid army contined to advance, and the Zoanthropes on the right destroyed the remaining Rhino.
Space Marine Turn 4
The Space Marines were quickly running out of men now, but the Black Templar scouts advanced towards the ruined building, while the remaining unit of Space Wolves moved to get back in the fight. The Chaplain and his two remaining men charged the Termagants. They killed many, but both Marines were also lost, leaving only the Chaplain to fight on amidst a sea of alien bodies. The combat between the Long Fangs and Genestealers continued to be a stalemate, with one being killed on each side. In the other combat, after barely surviving the Dreadnaught's attacks, the Carnifex decided it was done messing around and tore the machine apart.
Tyranid Turn 5
Seeing the approaching scouts, the Carnifex on the Tyranid right ran foward at full speed to cut them off from the runied building, but couldn't make it. The other Carnifex, unable to get at the Chaplain while he was surrounded by Termagants, advanced towards the remaining Space Wolves. The Termagants turned out not to need the help, as they dragged down the brave Chaplain, taking several more casualties in the process. The Genestealers on the Tyranid right stepped up their attack and finished off the Long Fangs.
Space Marine Turn 5
At this point, there wasn't much left of the Space Marine force, but the newly arrived scouts were spoiling for a fight. Eager for action, the Black Templar Scouts charged and finished off the Carnifex, before consolodating into the safety of the runied building.
Tyranid Turn 6
Time was running short now, and the few remaining Marines had little hope of holding off the attack from reaching the outpost. Termagants advanced to fire on the one remaining unit of Space Wolves, which was then charged by a Carnifex. The combination killed almost all of them, but the remaining two fought on in hopeless desperation. On the Tyranid right, the Zoanthropes fired their psychic blasts on the Scouts hiding in the ruined building, with impressive result. The Genestealers assaulted the remnants, but in their solid position, the Black Templars held them off.
Space Marine Turn 6
The Space Marine defense of the remote outpost had utterly collapsed. The Carnifex finished off the last two Space Wolves, and all that remained were the few battered Black Templar Scouts taking cover in the ruined building, and they could do nothing to stem the advancing tide.
The Marines had killed many Tyranids, but had lost almost their entire force in the process. The few scouts who remained were nowhere near enough to stop the tide of the Tyrand advance from reaching the outpost. Many of the refugees waiting for evacuation in the outpost would not escape, but would be devoured as the Tyranids overran the defenses. The entire continent was lost, and few were saved. The defense of world 18-D93 would now have to concentrate on containing the Tyranids to the Northwestern continent, and preventing their spread to the others.