Make no mistake, Goonies II was one of the best games for the NES. I would place it on the same tier with the original Zelda and Super Mario World. Definitely a top ten for the system.
The progression of upgrades throughout the game was Zelda like. You always felt like the next thing you needed to open a whole new aspect of the game, was just around the corner. Most of these upgrades were acquired in Goonies II's adventure mode. You would walk through rooms, smashing walls, searching for secrets. This was thern combines with the platform areas. There were plenty of platformers at the time but Goonies II did it right. The enemies were challenging and just a little frustrating. Hard enough to where I felt good taking them down successfully.
Combine that with the music and the length of the game and you have what would retrospectively be known as one of the few examples of a good game made from a film, or at least the premise of a film. You could have honestly slapped any film's title on this game and it still would have worked.
I highly recommend hunting down this game and giving it a try. It takes a couple of hours of gameplay to really get into it and understand how great the game is so make sure you have some time when you do. It will run using just about any NES emulator on any modern system but I'm partial to VirtuaNES myself.