fluxstuff: I felt they interrupted the pace, honestly. And the designs themselves were so dull - basically a closed arena battle. The first of them, with the hulking guard, was interesting, except that he's got a radar to where you are.
I suppose I liked the feeling I was outwitting the rest of the enemies, and felt I was just exploiting patterns with the bosses.
While I certainly agree that it could have been better executed, I think the manipulation of the patterns to defeat bosses is more in tune with the gimmick of the tribute to the 80's, an example that comes to mind is a Bowser encounter in Super Mario Bro's, Bowser shoots fire, you jump over Bowser when he is not shooting fire, you get the axe, no more Bowser, or perhaps you wait until he jumps to slip under him and grab the axe, or perhaps you use the platform, the pace/speed depends on the way the individual plays it.
The feeling that I take away from Hotline Miami and its bosses is a simple one, Hotline Miami is a ride, not unlike a roller coaster, the adrenaline fueled quick-thinking-on-your-feet-boundless-slaughter is the downhill speeding, which is fast, and adrenaline pumping, and the bosses are the uphill climb where one can relax, and the return to the boundless slaughter is the next downhill launch before you can relax TOO much. I would basically call Hotline Miami a well-working, well-oiled thrill ride that just works wonderfully. Sure, the slow parts of the ride may slow the pace, but it is still reasonable, and as stated before, agreeable, because what a ride it is to get there, and what a ride that follows.