I finally beat Dragon's Curse last light!
The last boss - the Vampire Dragon - was really difficult the first 5-6 times that I tried to beat him, but last night I finally buckled down and beat him with 2 medicine vials left over.
The most annoying part was that the save game doesn't save your medicine vials, so every time that I got a game over at the boss, I had to start over again with nothing but money, and then I had to use Mouse-Man to go get 3 vials before going through the final castle again.
Overall though, I really enjoyed the game, and I would recommend it to others. I never really felt that the game was too difficult or frustrating until the last boss, and even that wasn't too bad.