Maybe I cannot into Imperial Guard anymore, but I just got completely screwed by a normal/hard Necron AI in a 4v4 skirmish, me being the only human (allies are Space Marines, Orks, and Eldar). I spawned right next door to them on Penal Colony and felt nothing but pain for most of the game.
It started with sending a maxsize conscript squad + commissar to a critical point and getting ambushed by a wraith, ending in it seemingly reviving three or four times before I just called it a draw and ran. The mass of bodies in the way made it hard to tell how much it was hurting, so maybe the soldiers just kept knocking it over with melee.
Necron destroyers and the Necron Lord keep running at me from that front of my base, so I fortify with bolter turrets and a Leman Russ tank.
Then I
suddenly notice that my base is being hammered my Necron attacks from their base. They have sentry pylons that go through spurts of being able to fire at my bolters and sporadically decide to shoot the infantry command at times. I deploy earthshaker platforms, basilisks, and marauder bombers to underwhelming effect in my counter-strike. The swarms of destroyers and the Lord continue, with one wave having a bunch of deathmarks that succeed in shattering the morale of my cavalry squad before they even reached melee range. Fortunately, the bolters turned them into scrap metal.
Deciding that it was time to roll my own cheese wheel into the battle, I bought the General and slapped all the upgrades onto him and gave him a retinue of eight priests. Running into their base at full tilt, I hammered
fanaticism until all the sentry pylons were piles of living metal goop before running him back to the command center, lacking a single priest. On a side note: maybe I missed it before, but the General has an ability that lowers the morale of all enemies in the game and plays a
certain speech for its sound effect. Awesome.
Within minutes, more pylons had sprung out of the concrete and the Necron superstructure was shooting at me too apparently. By now I had all the production facilities, most upgrades, a nice pile of resources, tons of defenses on my north side, and enough green energy bolts flying around that I thought I was in a Green Lantern movie for a second. It was about this time that I built a Stormlord and noticed my Ork ally gettin' stomped flat by the Necrons. I deploy my Stormlord amidst a few squads of deathmarks and immortals to back them up and watch it get shredded by their weapons fire... How horrifying. Shortly after, the Necrons sent a massive wave to my Eldar ally, with me being in the sights next. There were sentry pylons right next to the Eldar buildings, too. I decided that I was probably done for and just called it quits there.
Melta and plasma didn't seem to help my guardsmen very much. Maybe I should use more Leman Russes next time.