For the record, if you're not really familiar with old Hammer horror films or the super-stylised silent horror movies, then you might be a little overwhelmed by the aesthetic of this film. It borrows heavily from the highly dramatised films of old, and obviously is a sort of homage to the Phantom of the Opera as represented by the agonised stylings of the incomparable Lon Chaney.
However it is still an action film, and it really does succeed in this fact, with a truly outrageous helicopter chase towards the end which is absiolutely hilarious yet at the same time finally convinces the audience to label the eponymous, delusional, unfeeling but heroic Darkman as badass.
As for Liam Neeson, he's obviously enjoying himself, acting so hard he's practically chewing the scenery. He manages to create a complex, disturbing and enigmatic hero in spite of, or perhaps because of, Darkman's madness (caused by his physical imperception to pain and deformity by the local big bad's goons).
So, in short, if anyone is looking for a damn good superhero movie that still makes short work of it's predecessors, look no further than Darkman, an intelligent, highly enjoyable movie.