How do you beat Thardus?

Thardus only has a few attacks - he'll get into a ball and roll at you, which you can avoid by Morph Ball Boosting away, he can send rocks flying at you and he can also shoot ice along the ground at you, both of which you can avoid by jumping/running out of the way.

To see Thardus' weak point, put on the Thermal Visor (D-Down), lock on (L-Button) and attack the red, 'hot spot.' Keep attacking with either charged up Power or Wave Beam shots, Missiles or Super Missiles; when you've dealt enough damage, your Visor will go bright and you'll need to switch back to your Combat Visor (D-Up). The spot that you were attacking will now be a blue, 'cold spot' - lock onto it and attack it again.

Power Beam shots are stronger than Wave Beam shots, but Wave Beam shots are better because they home in on the locked on spot - use this on the arms and legs. Super Missiles are even stronger and home in too, but they can be wasted if they get blocked by another part of his body - so use them on his head, shoulders and chest.

If you get low on Missile Ammo or Health, destroy the rocks that he throws at you to get some refills.

Other than that, just keep attacking his hot and then cold spots until he's history - good luck!

Easier still double jump onto rocks near any corner, his ice attacks wont work and you can grind him down with ease