Ratchetruler, from what I found, there are 3 different times, one of theme being the developer time, I can't remember what they call the other 2, all I remember is that they are creators of the game, but you beat 1 of those 3 times, can be any one of them, and you will get that skill point. The first level, the easiest of the 3 to beat is like 7 minutes and some odd seconds, and after getting all of the upgrades, I beat it with ease, but as for beating it with cheats activated, I guess it depends on the cheat that's activated. If you activate weapon size, head size, or screen effects, then more than likely it will still work, but I don't know about the unlimited ammo cheat, as I have yet to unlock it.