Darkwing Duck

"The Liquidator, Quackerjack, Wolfduck and other F.O.W.L. agents have been looting various parts of the city. These robberies may be part of a larger plan by F.O.W.L. to seize control of St. Canard. Do whatever you think is necessary to retrieve the loot and bring these fiends to justice. The fate of the city is in your hands. Good Luck, Darkwing."

--From the NES Darkwing Duck instruction manual.

Overview:
F.O.W.L (The Fiendish Organization for World Larceny) have organized the deadliest evil doers to help them in their evil scheme. S.H.U.S.H. (the secret crime-fighting organization that's so secret, nobody even knows what the letters stand for) calls in their best agent. It's up to DarkWing Duck to stop them with his Gas Gun!

Not exactly a spin-off, but Darkwing Duck does take place in the same world as Duck Tales and features cross-over characters like Launchpad McQuack and GizmoDuck.

Directions:
It's like Megaman, but with a Duck! It's pretty simple run and gun action, however Darkwing's gas gun has three other functions that you need power-ups for.
Lightning: Shoots two diagonal bolts
Heavy: Tosses a cloud of gas that shoots off left and right once it hits the ground.
Arrow: Shoots an arrow that can stick to walls and be used to stand/hang from.

Also, Darkwing can hang from almost anything, Ledges, Hooks, Street Lamps and more!

If enemies are shooting at you, you can block by pushing up!