The game started with heavy tyranid advance on right edge (from Ork viewpoint), as the Ork town was surrounded by razorwire and denied efficient advance from therein. However, as Tyranids quickly advanced hidden Ork battlewagon and speedsta kult mobs in right edge and Snake bite artillery in the Ork town were revealed and lots of Tyranids were lost in defense fire.
On turn 2, reinforcement buggies arrived and Ork speed kultists kept their position trying to slow down the advancing bio-horde. But as mycatid swarm reinforcements dropped behind the right edge kultists, they were completely wiped in upcoming assault phase.
The picture is taken after Orks had moved but Tyranids had not yet, and thus the mycatid swarm drop to the right-hand corner is not on the board, yet. The ex-swarm was destroyed on turn 1.
On turn 3, horrible swarm of Tyranids were dropped behind the Orks in town. However, combined firepower, fighta bombaz attack, some reserves and play of total of 3 psychic blasts resulted in total annihilation of the most powerful tyranid horde behind the lines. However, main Ork big horde fell back and did not rally.
The picture is taken after Tyranids had moved but Orks had not yet. The Tyranids had to move first as otherwise Ork fighta bombaz would have bombed their swarms into oblivion.
On turn 4, Tyranids kept on advancing on the middle of the board, while the missing Ork warlord mob and the last Tyranid mycatid swarm, consisting of lots of genestealers, arrived to the Ork town. The warlord crashed into the remaining Tyranid artillery units in the corner and thus genestealers were left without potential assault targets. Meanwhile, Ork buggies repelled attacking tyranids in the middle of the Ork's edge.
The picture is taken at the end of turn 4, after Ork warlord mob had wiped mycatid artillery out of board and buggies repelled Tyranids on the right edge.