When you consider that the Gotham City universe is absolutely absurd, this isn't a bad movie. It was made at a time when we were just on the verge of superior effects and makeup. I must say it does a good job with the makeup. But back to the absurdity. Gotham is just that. It's a campy and ridiculous setting for a super hero. That's why picking Tim Burton to direct this was just what it needed. While I am not intimately familiar with the comic books, I do know enough of the setting. I believe Burton did a good job staying true to the old school comics which is basically all this movie had to go on. The Batman of today is a much darker and more human-like character. But this is a true comic book movie.
The acting from Nicholson is brilliant. Never mind the Dark Knight's Joker. Nicholson and Ledger were really playing two different roles. Nicholson's was a much more fun psychopath with less of a grip on reality. He really makes the character fun and, considering who he is, is a perfect man for the role. The rest of the acting ranges from OK to pretty bad. But that isn't a huge deal because the movie really focuses on the Joker. Speaking of which, I could have really used more Batman and less Bruce Wayne. After all, I watch these kinds of movies to see the cool action stuff.
Bottom line, it really is a "see" due to the performance by Nicholson.