It is like Megaman in everything... except for the controls.
I might be throwing around the rip-off title too harshly, though.
There are a couple of new things implemented here. Like that cape used to block various attacks. Or the fact that Darkwing Duck can grapple. So it's not completely like Megaman, I guess.
So far you're probably thinking: "What's so bad about this? I mean, arguably the best Disney cartoon show mixed with Megaman, what could go wrong?". To answer that, a couple of things.
While the levels are pretty varied, some of them get incredibly frustrating because of the different enemy types. The hit detection is awful and cheap-shotting bad guys are inevitable in this case. Here's my favorite part, though. When you destroy an enemy while dodging his attacks (and inevitably stepping back), you might cause the screen to scroll. When you finally go forward, the aforementioned dead enemy returns with full health ready to kick your ass. I acknowledge that it is common for old games but, here, it is a **** game killer. Believe me.
The controls are pretty bad. I've lost so many boss battles because the grappling is quite hard to get used to. The jumping is okay, though. Oh, I forgot, the grapple detection is absolute crap. There is no specific spots, people, jump and **** pray.
The boss battles are inventive but boring since everyone takes so long to die. And while they're jumping from platform to platform, you've got to dodge random henchmen or other crap which is ridiculously hard.
In the end, Darkwing Duck is not a very good game. The graphics are okay and it could've been good but it's just too frustrating for all the wrong reasons.