Awesome Music: Weasel Man and Laser Man from the first game arguably have the most awesome music.
Game-Breaker: Rapid Fire can be abused... often. Laser Wave is another overly powerful attack.
Improved Second Attempt: While the first Rockmen R game is far from terrible, it suffers from questionable and unfair level designs, subpar visuals, slippery controls, and obtuse secret item placements that sometimes require an online guide to even find them, all while running in a choppy frame-rate which contributes to delayed inputs that not even the NES would not find acceptable. The sequel rectified many of the first game's shortcomings with better visuals and smoother framerate, tighter controls, more polished level design, and better secret hunting.
That One Boss: Piano can be this way in her third appearance in the first game.
Waltz Man's stage is also a pain. Falling traps positioned near bottomless pits or spikes that you'll likely fall to your death in (the spikes at least gives you a bit of time to escape to safety). Those charging knight enemies don't make things any better.
