I was up 'til 2 a.m. Tuesday morning beating Bonk 3 CD on the Duo. I don't know if the difficulty is any harder, but I didn't do quite as well (1,092,980 points and 48 left over lives). I f'd up on level 3-3 (I think, it's the one with a bunch of extra bonks on either side of the exit elevator), missing out on at least 20 smileys and a dozen extra lives. Don't ever pick up the flower copter thingy when you're still full size - makes it impossible to get to the other areas. I was also having a hard time consistently completing the springy flower bonus round, so I switched to the jet roller pipe one. It's worth 400 less points, but I could pull it off 95% of the time.