As it Stands, Infeasible
There's not just one or two problem with this thing existing. There are all the problems wit this thing existing. Let's just start this point by point.
This isn't a cephalopod. I like the Cthullu mythos as much as the next person, but cephalopods have a few very specific traits, like not having bones. That means, for whatever reason, this is actually a mammal or reptile that has decided to evolve for no discernible reason to look like Cthullu. It makes no sense for this creature to have 'mouth tentacles' when it's primary means of offense seems to be lightning things to death. They'd only make sense if this was vestigial, but since this isn't a cephalopod-based, no Cthullu beard.
According to the (self-proclaimed) Official Evolve Wiki, it can hover indefinitely. It doesn't say how, so I'm going to assume that it was through using lightning, judging from the tentacles. Now, while that makes no sense, maybe it's using magnetics and flying by repulsing the magnetic field of the planet it's on. Except... that can't work either, take a look at this question. Take a look at the second answer, the short of it is that we need a diamagnetic field the size of the planet's magnetic field.
I mean, of this thing's attacks, the only relatively feasible one is Aftershock, which seems to be some kind of area-of-effect electricity attack. Banshee Mines act like sticky grenades from Halo, which aren't terrible, all things considered, it's feasible for an organism to produce to be able to produce explosive material and then somehow put a timer in it. It just seems like something which is theoretically possible but too complicated of a process to be evolved without repeatedly killing the animal in the process. The bad ones are Vortex, which projects a wall of 'elemental energy', which sounds more like a spell in D&D, and Lightning Strike which doesn't strike from the Kraken, it strikes from the sky where the Kraken isn't, somehow.
Size & Energy
Last one. It's a kaiju, basically, like all creatures in Evolve, and thus because of our helpful friend the square-cube law, it basically shouldn't be able to have anything resembling a human bone structure which it does. An armored exoskeleton, like the Goliath appears to have would be helpful, but the exterior is clearly this scaly/leathery thing. Not to mention that the energy needed would be absolutely nightmare-ish, especially considering that this thing appears to have the energy to chuck around lightning bolts, which is an average 1 billion joules of energy. Compare to a human body's 340 million joules. In other words, each bolt would require 3 humans to be consumed.
What is Feasible
Well... let's say a creature evolved in an environment full of powerful natural magnets, and a world that had frequent storms full of lightning strikes. Let's also give it some naturally occurring pools of electricity-rich liquid, maybe a giant salty lake with copper & zinc disks in it. It's possible to evolve a creature powered by electricity, which has harnessed the power of a magnetic field to bounce around the magnetic-field rich environment. Maybe it can also absorb lightning bolts directly for energy, and has some form of an organic battery inside itself to be used against predators or for stunning prey. It's reptilian in nature, and it's mouth is reminiscent of an Elite from Halo, with separate jaw bones instead of a single jaw. That is the closest I think you could get to the Kraken.