Game #1 I set up the Orks garrisoning the two Gunz mobs on either flank of a 'Big' mob, the second 'Big' mob in the centre leading the Great Gargant and the rest of the army.
From the camera's perspective, TRC teleported the Terminators on the right-hand Gunz mob (in the town), won the initiative and anahilated them. He also used his upgunned Assaults formation to assault and break the left-hand Gunz mob. Both armies then concentrated on gaining the centre of the battlefield with the Orks pushing forwards various formations to lay BMs on the Termies, and the Sallies replying in kind. It culminated with the central 'Big' mob doubling through its compatriot to lay BMs and support the assault of the other 'Big' Mob on the Tacticals that had arrived to their front. However, despite having a third of their number in B-B and some 39 Ork units assaulting or supporting, this achieved a grand total of '1' dead tactical (not even '3' TRC

)  - and the Orks lost '12' in reply and subsequent hackdowns. To add insult to injury, in the following turn the Marines scouts used their infiltrator ability to mount a clipping assault on the flank of the remaining 'Big' mob, and broke it as well (with the support of the victorious Tacticals) for no loss. So with the Orks down to two disilusioned mobs and a Great Gargant, the game was stopped and reset.
Game #2 used exactly the same setup except the RH Gunz mob was put on OW (to discourage the Assault Marines). TRC switched the Termies to drop in on the Big Blitz brigade by the Blitz, but one stumbled and even the SC reroll could not get the formation to budge. Subsequently both Gunz mobs and a small Blitz brigade killed some of the marine transport using their Zzaps and OW fire, and with the Great Gargant steaming up the table, the Orks had most of their formations intact at the end of turn #1. Meanwhile the Sallies ended up with the Terminators broken (the THawk flew by without trying to retrieve them) and most formations severely mauled; and the game slipping rapidly from their grasp after the first activations of turn #2.
TRC suggested that the remarkable difference between the two games lay in the different tactics adopted by the Orks. In Game #1 the Orks were pushing formations forwards which were being picked off in turn by the various advancing marine formations. This strategy was precipitated by the loss of the two Gunz mobs at the outset. In Game #2, the failure of the Termie assault allowed the Orks to use these Gunz mobs, and the subsequent activation sequence meant that it was the Marines who were forced to advance in a hail of fire.
Personally I lay the blame squarely on my fickle dice which threw abysmally in Game #1, and then made a stunning comeback in Game #2. And before anyone asks, TRC very bravely used my dice throughout and seemed to achieve fairly consistent results - though he did throw 5x '6' saves at one point (from 6x dice). I replied in kind on game #2 saving 4x scorchas from the ravages of his Tbolts.