Seriously, buy this game. You still have like two hours.
BTW this can be pant-stufftingly scary. After trying like 5-6 times to clear out the bandit base near the research facility, I finally got a good route up through the building and I was about to kill the guy with the second key to the nearby facility. I was disconcertingly low on health supplies and ammunition, and I was creeping up the back stairway (the entire building was basically dark) I was coming around the corner when WHAMMO. Right there there was a bandit crouching down unseen around the corner lighting up the whole screen with bullets and his gas masked face almost making me lose control of my bowels right there. Fortunately for me, though, I had my Viper 5 out and offed him right there.
Great game.