#38) Metal Slug 4 (NG/PS2/Xbox/Wii/PSP)
Metal Slug 4 relied more on cheap enemy placement for difficulty instead of pure great game design, and I fail to remember most of what happened in the final two stages, but it still doesn't fall too short of its two predecessors.
By the time this list is finished, you'll realize what a huge compliment that is coming from me.