User blog comment:GeneralOwnage55/LP upgrade suggestions box./@comment-1330314-20110926221052

Although the order in which you'll upgrade your weapons is up to you, I suggest the following:
 * Don't take the Reflector Plate upgrade to the Drill, the Bouncing Bullets upgrade for the Machine Gun or the Electrified Shells upgrade for the Shotgun, since they're less effective than the others.
 * Start by taking the Drill's Side Augers upgrade, since by dealing more damage it'll also reduce fuel consumption as a side effect.
 * Get the Drill's first two upgrades before the others, and then specialize in a weapon whenever you can.
 * In the long run, choose between getting the Rivet Gun's Heated Rivets upgrade and the Spear Gun's Faster Mechanics. You can't get them both, and although less powerful than the Launcher's Cluster Bombs upgrade they can still be fairly helpful.