After finding the microchip in a random vent in the furnace, Butch heads for the monorail to New Generation's labs only to find a space shuttle bug out as it takes off for space.
No, seriously. They had one job. Anyway, this level is another reason why playing on Hard is a waste of time. The designers just threw all the rules of good game design out the window for this mess of a level. From the start, you're overwhelmed by more fat guys than at an all-you-can eat buffet. On Hard, the rocket launcher would only tickle these fat bastards as they pump me full of lasers. Don't judge me; play it for yourself! Once you get to the massive tunnels, things only get worse as more and more fat guys surround you from both sides with no cover. More like "Fat Hunter", am I right? By this point in the game, it's also impossible to dodge the lasers even if you strafe backwards diagonally because they just move faster than you can.
Someone on gamersgate.com actually mentioned that you can alter the .XML files to speed up your running speed. I couldn't deprive you of the true Rat Hunter experience, though, could I?