Good, but the graphical glitch was annoying.
I experienced the same graphical glitch that RickyTheFish complained about. It looked to me like the game's shop and level-up perk menues were being overlaid in a small gray form on the middle of the screen - the gray boxes seem to correspond to the two menues' items and description bar.
Other than that, it was a fun, if repetitive, time-waster. It was annoying that there was no 'endless' level-up feature to keep spending my points on after all the stuff I could buy was bought. Also annoying that there was nothing to buy after I had the two lasers for my arms. I wish I could've upgraded the other guy's guns.
Another annoying thing is that my backup guys didn't shoot at the King, and their basic guns (and Hamilton's not-quite-basic guns) didn't really do enough damage to keep the other ground-pounders off me, necessitating that I take my attention away from the task of requisite robo-regicide to clear out the riff-raff. This left periods of time in which my fire was off the King, and periods of time in which my backup wasn't doing anything remotely constructive, both of which were annoying.
Still, it was diverting.