I was hoping this would be a strategy game, like X-COM. :-(

What makes this game fun, in your opinion?

Blowing up buildings and lots and lots of insects.
Also UFO's that drop more insects.
And giant robots.

Seeing giant insects eating japanese game developpers.

Getting a higher killcount than a serious sam game.

Watching the trailer I kept expecting to see "Would you like to know more?"

Pass. $50 non-sale price tag and 16 DLCs a day after release, even if they do all appear to be cosmetic.

If anyone is playing this, how do classes work exactly: is there some sort of levelling attached to them? Are you encouraged to use certain classes for certain missions, or just pick your favourite and stick with it?

Of course there's that many dlc's. O_o
It came out on console more than a year ago.

You can fault them for not including it in the main game now but what else would they do, not give us the dlc?
From what I remember different classes can use different weapons, I'm pretty sure classes are separate in progress though I might be wrong.