Canned meat has a use in a situationally useful crafting recipe, so you may want to keep a can or two around, just in case. And of course, there are the usual inventory concerns: if you're already carrying four empty cans, but aren't too badly wounded, you may want to hold off eating until you find a use for them.

Ok, as I've now managed to get to level 9 I think I can advice on the guards. Make sure to sneak around a corner or behind a door and wait for them to come to you. Use a shotgun or similar weapon that does a lot of damage upfront. The AGL kills them in one grenade but they can still fire when tagged with a grenade. Profit As for the scientists (which are basically upgraded guards) the same tactics apply apart from the fact that they take more punishment and deal more damage. Still one AGL grenade kills them, otherwise good weapons include the teslacoil.

Item containers (placement and items) are randomized, enemy spawnpoints are randomized, map is randomized. Map is constructed out of rooms that are then connected into a level. You can't really plan for a run as there are very few constants.

Keep the side where the knife renders toward enemy and constantly backpedal. That is the basics of my knife strategy. Edit: at an angle toward enemy rather. After having done some more melee to try out what works best I found that for me it works better if I time my stabs rather than spamming the attack button. Takes more practice but it seems more consistent.