Addictive!
The sheer level of overkill you can reach is amazing.
I liked especially how you can kill yourself with the nuke (hint: you have to overpower it)
Although it's strange that curb-stomp detonations don't so much as hurt your boot, but that attack (which is not melee, hint hint) is lethal.
I quickly went from throwing rocks at ants to amassing huge piles of dead and melted critters, doing mean things like lopping off the tops and bottoms of segmented creatures, and headshotting enemies with nuke drops. Aside from lessening the rifle achievement (the only one I haven't gotten simply due to the rediculous amount of kills necessary), this game is a 10/10.