Obviously a style piece, but you are using the same tracks and wheels from a normal sized tank which makes it look like you just stacked some tanks on top of each other and looks awful.
Right size the tracks and wheels to match the style!
I'm guessing because of the size it's primarily used as a homeland defense. The logistics of moving it far a field would be a nightmare. But if it fills a primarily home land defense role, I wouldn't recommend using nuclear artillery. The fall out would decimate your population base and cripple the economy under the increased cost of medical care for radiation poisoning, starvation and the plethora of diseases that would be rampant.
It can drive under inland seas and large rivers since it's powered by a nuclear fusion reactor.
It's mainly transported by cargo ships across the ocean, though. It's not meant for defence at all. They can be used on other continents provided you have a cargo ship big enough to carry it there and offload it at a sufficiently sized dockyard and it doesn't get holed by a submarine.
Nuclear weapons are the primary weapon because it's supposed to fight entire battalions of normal tanks, GEVs, and armoured infantry.
I would smell in this manga/anime or nationstates. In that case realistic aspects of design are not important. But still, it's a good drawning. Totally unrealistic and "silly" of course but as drawning, it's good.