Press the '`' key to quick kick, or the '1' key to switch to. The Might Foot is a nice weapon for things like breaking open air vents, and sometimes you can kill Pigcop and Enforecers around corners. I once killed the first boss with only my foot. A interesting fact that some people don't know is, when you switch to the weapon with the '1' key, it kicks rapidlier than using the quick kick.
Press '2' to use. The pistol is the weapon you start with. You start with 48 ammo, and get 12 ammo a clip. When you pick up another pistol, you get 12 ammo as well. This is alright for Asault Trooper's and Asault Captain's, and maybe Pig Cops, but that's about it. When used on a Pig Cop, it will take about 14 shots to kill him, but you really oughta use a better weapon like the shotgun.
Press '3' to use. This weapon is quite a bit more powerful then a pistol, blasting at least 7 bullets out of its barrel at a time. But a pistol can work better when you are very far back (so I hear). This works great on Asault Trooper's or Asault Captains. One shot will easily kill them. You get 10 ammo a pack, and on easier difficulties 10 per shotgun. On harder difficulties, you get only one measly little shot per shotgun. Your shotgun can hold up to 50 maximum ammo.
Press '4' to switch. This weapon is very rapid, and is great for single or groups of monsters. You get 50 ammo per gun or pack, with a maximum of 200 ammo. This is the BEST weapon for Sentry Drones. Use it wisely though, because 200 ammo isn't terribly much for a very rapid gun when used heavily.
Press '5' to use. This weapon can kill most monsters with only one shot. As a matter of fact, every monster but the boss in shareware can be killed with one shot from this baby. The RPG stands for Rocket Propelled Grenade. This weapon can kill you if your enemy is standing right in front of you when you shoot, or if you're facing a wall. 5 shots to a pack, and same for the actual gun. You have a maximum of 50 ammo.
Press '6' to use. The Pipe Bombs are different from most weapons in other 3D games. You can toss 1 or more out, and whenever you want to, press the plunger to set them off. To toss out more than 1 at a time, press again 6 after tossing out the first one. These are even more powerful than the RPG (actualy just bigger radious), but aren't really great for in combat. Use them for putting in front of doors and opening them, and waiting for the monster to come out, or toss them down while you're high up and kill them before they have a chance to think (not that they would anyway).
Press '7' and get ready to squish. This is more of a weapon for show, but it's nice for tunnels. It is slow fire, and then you have to go over to your enemy and squish him, which it does automatically when you get close enough. Until he grows back to normal size (which will take a short while, maybe 15 seconds), he can't hurt you at all. It has a nice sound to. Works best in tunnels, and isn't good for groups. 5 ammo per crystal, and the 10 for the gun.
Press '8' for action. This is a GREAT weapon. It fires RPG like missiles, 10 per second, and they are the best weapon for any boss. Although the missiles aren't as strong as RPG shots, the rapidity more than makes up for that. 15 ammo per box, or for the gun. Maximum ammo, 99.
Press '9' to use. This is one of my favorite weapons. They work GREAT in DukeMatch. You can put one on a wall, and in two seconds, it'll activate. If anything blocks the beam, it'll explode with a wider radius than a Pipebomb. If you put one up in DukeMatch, and it kills someone in your next life, it still counts as your kill. Another interesting thing about these, which is likely a bug, is when falling down real far, you can put them up if you're facing a wall, and while placing them on the wall, you will stop falling for a short amount of time. I've managed to keep from getting hurt at all a couple times using this trick, but I usually to get hurt a little.