There are a TON of great weapons in this game!!! Each time you open a new planet, the vendor there will have a new weapon offering or two for you. The more you use a given weapon, the more it gains in power (as shown by the red bar beneath the weapon's icon in the top left of the screen). If you fill up the power bar it "evolves" to a higher form of weapon.

If you have your memory card from Ratchet & Clank 1, then at a certain vendor you can get for free some of the old weapons! If you don't have a memory card you simply have to buy them. Note you CANNOT get the RYNO from the old game - they now have a RYNO 2 :)

As if that wasn't enough, when you get platinum bolts you can give your weapons SPECIAL features like lightning and acid!!

Note that your wrench doesn't power-upgrade. There are specific locations in the game where you find a new, better wrench.