We then had a brief chat about the game and Andy said that in retrospect he would have used his Thunder Hammer/Storm Shield Sergeant to try and block off the entry points at the bottom of the map and then set up some fields of fire to take out all of the Genestealers entering at the top.
I figured it was a good a tactic as any since at least the Sergeant would at least buy me some time even if he died early on. And die early on he did. However, he did manage to get me a couple of turns in which to set up my interlocking fields of fire. Marine of the match would have to be the guy with the Chainfist as he managed to hold off one corridor before covering one of his brothers and then he managed to reinforce the Assault Cannon Marine which meant that I could just about hold off Andy's final push. In the end I think I managed to pull out the victory because Andy tried to split his Blips and then held off a turn too long on attacking as he was (rightly) scared of the Assault Cannon. Unfortunately for him that just allowed me enough time to reinforce and improve my position.
Here's a pic at the end of the second game showing my three brave Marines and how they managed to cover each other:
I do enjoy playing Space Hulk, it's so quick and straightforward and it always seems to come down to the last couple of Marines desperately trying to hold out for victory. It's also more tactical than most boardgames and the pressure is really on as the Marine player when those sands of time are running out.