I opened the safe by systematically trying the color combos. The scenes changed too fast for me to recall the colors, but you can get it in a manner of minutes.
3/5
I made 340K+
17K hitpoints
900+ ammo
but I had to quit because it was lagging my system and do I mean lagging my system. Also, the Uber Gun does not really have a spray factor at all. The pac man gun is the best you should aim for.
I died on day 27 and then I chose to keep on playing and it gave me extra money. I then bought a crap load of health, almost lost again, but got out with luck and just a few hit points. After you get the pac man gun, the game is really easy