Anyone have individual reviews on each game?
Ducktales: Fun platformer with some unique mechanics that weren't really copied by anything else until Shovel Knight. Big, sprawling levels for an NES game that let you wander around like a series of mini-Metroid style games. Absolutely worth playing if you're interested in the NES era of video games, it's really a classic.
Ducktales 2: Basically more of the first game, doesn't really do anything noteworthy itself but it's still a lot of fun.
Rescue Rangers: A fun if slightly clunky platformer with Mario 2 style pick-up-and-throw combat. The big draw here is 2 player simultaneous co-op, a rarity on the NES. This game's impact on co-op games can still be felt as recently as the New Super Mario Bros series, this is where the 'pick up and throw your friend' thing really came from. Singleplayer it's alright, but in co-op it's great.
Rescue Rangers 2: Not as good as the first game, but still fun with two players. A solid addition to this pack but not a main draw (except for how expensive the real cart is to buy).
Darkwing Duck: Built out of the same engine as Megaman 5, Darkwing Duck takes the Megaman formula in some interesting directions. It still has the structure that lets you pick who to fight when, but Darkwing has more platforming tools than Megaman and less weapon variety. The boss fights are more imaginative than the other NES Megaman titles. Personally I think Darkwing Duck is a great spin on that formula and worth playing if you enjoy Megaman.
Tailspin: A side-scrolling shmup. Not really anything special, in my opinion. A fun addition to the pack but not a game I'd buy on it's own.