Needs work, but that's where most start.
This thing needs a lot of work, but that's to be expected considering it's a first work. So keeping that in mind, here's a few suggestions that might help in the future.
Sprite movies can be good. That said, if you're going to go sprite, you should go all the way. Mixing sprites with hand-drawn stuff usually doesn't work as well as going completely with one style or the other.
Which leads to another point which, to be point blank, is that your hand-drawn artwork needs a 'lot' of work. Flash is a very visual medium, and without good artistic ability, you're going to find it very hard to really become successful with it. Practice, practice, practice.
Lastly, and probably the single hardest thing for you to handle on your own, is the sound. You tried to keep the spirit of the game alive by using the original sounds, and that's commendable, but honestly they're quite dated in this day and age. The voice-work...is passable. It's far from being great, but really there's only so much you can do with a crew of one guy. Maybe invest in a better mic?
You say you're proud of the work, and you should be if only because Flash can be very daunting to learn. So take that pride, and use it as a driving force to get better.