Okay, time for the antithesis post...
ALL TIME EASIEST BOSS... after the longest and hardest setup.
I was unfortunate enough to own a copy of Ultra's "Teenage Mutant Ninja Turtles," a functionally simple platformer whose complexity lay in the programmers' humorless idea of a joke by designing mind-numbingly frustrating levels and maps. The design is so specific to the level, in fact, that certain jumps make you appreciate anew the difference between a couple of pixels.
Levels include a three-platformed drop through turtle-sized holes while beating some spiked walls looking to squeeze you into green goo; a level boss who's located on the other side of a masterfully timed jump to a platform located off-screen (i.e. you don't know it's there) that must be made in conjunction with a masterfully timed projectile meant to eliminate the enemy waiting at that side, whose presence limits your ability to land the jump; the infamous Hudson River, whose contents include 8 bombs that must be defused, all in the time of three minutes (a timer is on-screen) while your precious turtles suffer damage from relentless omnipresent life-sucking... plants... with no method of replenishing life in sight.
All this and more to set the path for... Shredder, of course. Arriving in, yes, a Bolt of UberLightning, Donatello cowers in the corner as the final boss of this unfairly difficult game strides over to undermine the skill you thought you had for even getting this far...
Just to take it up the ass when one swipe from Donatello's Bo knocks him to the floor, allowing for a half-second delay animation, followed by a second swipe from the Bo, followed by a third, and a fourth, and...
That's it. Teh Suxor. Booooooorrring.
The game bitched at by