At times I feel like this is a very underrated villain. Many people know of Metallo and how is core or "heart" is a chunk of Kryptonite, but not a lot of people really care to talk about him or acknowledge just how kick ass he can be.
So I did some digging to find some feats and show off what this Cyborg is capable of.
Super Strength & Durability
While kryptonite acts as Superman's Achilles heel, the affects are not as instantaneous as many believe. Once coming into contact with kryptonite Superman's powers will begin to fade; however, this may take some time. If he acts quickly Superman can extinguish the threat before his powers leave him. So what does that say about Metallo? I feel a common misconception is that Metallo has no real power besides the Kryptonite. In truth he has strength and durability in abundance. Here are some examples.
Metallo battles Superman, without the use of Kryptonite.
During this fight, Metallo showcases tremendous strength by launching Superman through a city building
Metallo's upgraded body is durable enough to take repeated blows from Superman and the fight was brought to an end only after outside interference.
With the use of Kryptonite, Superman is at Metallo's mercy.
By the looks of it the first and second scan, Metallo knocked Superman a couple blocks away.
Being that his brain is really all that is left of his human self, any harm that comes to his body is of little consequence.
In speaking of Body.
Metallo also has the ability to absorb other machines and reconfigure/morph himself into whatever he may need.
Battles Electric Blue Superman (yes that was a thing)
Metallo showcases his ability to absorb and redirect energy. Given his ability to absorb other machines, he can also grow to an incredible size. Though it looks like he needs a tremendous power source to maintain this size.
Absorbs numerous machines
This really speaks volumes as to how dangerous Metallo can become.
Improvised weapons and tools
As seen here, He can morph his limbs into whatever he may need for the circumstance.