On the Genesis version, it took me a while. First, I was stuck on Level 3 for a long time because I didn't have the skills on that bike. Then, I was stuck on Level 6 for a while because I couldn't get the Snake pattern down. Next place I was stuck on was Level 7 (inferno level). The next place that took me the second longest time was Level 9. Luckily, I had a past issue of Nintendo power to help me through the maze (and that's when I realized that Battletoads was on the NES as well). The race was tough (Level 10), then the handbike level against that orb of doom was tough for me...why? The up button on my Genesis controller wasn't working well, so i had to wiggle the cord and make sure it stayed there so the up button would continue to work. The level that took me the longest was the Revolution (Level 12). I swear, I gave up so many times on that damn level because I kept falling to my doom when I tried going up the platforms. And those damn cloud enemies? Just more frustration added on me. At the end, I was surprised that the boss was SO easy.
To this day, Level 9 and Level 12 are the two levels I have trouble on. Anything else, I can pretty much do.
While I'm on the topic of Battletoads, does anyone remember the cartoon?
Most amazing jew boots