DarkHorizons.com had a spoiler-free (and decidedly positive) review of Return of the Joker posted up today. Here's the review:

"Batman Beyond: Return of the Joker" - A Review by 'Major Tom' (Positive - No Spoilers)

The promotional screening tapes for the animated film "Batman Beyond: Return of the Joker," due out October 24, are now making the rounds. Having just watched the film, let me just say that Warner Bros. made a rare wise choice when they tapped Paul Dini to script the live-action Batman Beyond movie. "Return of the Joker" just plain rocks.

The animation quality falls somewhere between the weekly series and the best anime, with the fight sequences being particularly well-designed and exciting. The new Joker is creepier, more menacing than in the previous series, and Mark Hamill's Joker-voice is slightly deeper to reflect this change. All of the voice-acting is solid, including Will Friedle as Batman, Kevin Conway as Bruce Wayne, and Henry Rollins (!) as a member of Joker's gang.

As for the plot: I'm not going to be the one who spoils the shocking (and I mean SHOCKING) revelation of what happened to the Joker, Harley Quinn and the original Bat team in a flashback sequence that's definitely the most memorable scene of the film. It's not what I expected, I'll tell ya that! Suffice to say, it wouldn't have gotten past Saturday Morning TV censors! And the
way the Joker is brought back is inventive and heart-wrenching at the same time.

Paul Dini's writing is superb. The characters are better developed, the dialogue more believable and situations more dramatic and affecting than anything Joel Schumacher or (dare I say it?) Tim Burton brought to the live-action series.

I HIGHLY recommend this film to anyone who has become disenchanted with Batman or isn't sold on the "new, hip" Batman Beyond. "Return of the Joker" is a reminder of how cool Batman can be in the right hands.