Was playing on normal, with complete focus on artillery beam and defense, and nothing at all in weapons. It was comically good. It was an exceptionally lucky run it would seem, because I hit all the right spots and ended up unlocking the crystal cruiser.
Had a full crew and maxed out teleport and med bay, using frequent hit and run tactics between beam strikes. It was so fun, you have to try both the ship and this particular playstyle if you haven't yet.
But wouldn't you know it, in true FTL fashion (though it was actually completely my fault), on the last node in the crystal sector, right before the flagship sector, I lose sight of the enemy hull health and my beam charge, and end up frying my two black belt mantis buddies along with the enemy ship. Right before the flagship encounter!
That was me for about 5 minutes. The rest of my crew were mostly engi and zoltan, which I needed on the ship. I thought all was lost. I've had some poor luck as far as items went this run, and only managed to secure one lousy defense drone, so things looked grim, but the crystal engines man, and the rock firefighter on my crew stepped in, in heroic fashion. Complete fighting rookies, they bravely assaulted that triple missle launcher, and valiantly defended against those breach drones, and mass invaders on stage three. Barely pulled out a victory in the end with that skeleton crew.Shame I didn't record any of this, but I suppose there are too many people putting up videos of their runs on this game as it is. I just wanted to share the story since the shock of frying my mantis right before the boss followed by a hard fought victory anyway really made that run special. Oh and also to urge those who haven't tried the no weapons artillery beam with constant teleport harrass playstyle, to give it a try.
I do it with a Halberd beam and sucking at math. 
lovely... (my brain falls asleep at the wheel) nothing could be better than taking down a shield bubble right before a beam hits.. and There It Goes!! ripping the medbay to shreds, and wounding the enemies that just managed to repair it, and now it will silence that damned missile launch...(ship blows up)