This game is a blast.
There's a lot of variety in the torture options (there are basically four you can do to anyone, but there seem to be a lot of "special interrogations"), at least in the few levels I've played so far. There are also a few creative ways to kill people. Dropping engines on their head, sending an unmanned forklift into the platform they're on...
One thing the demo didn't indicate is the light RPG element. The better you do in the mission stylistically, the more points you earn (you can also get multipliers by not getting hit between torture sessions). You use those points to give yourself better body armor, more ammo, better aim, etc. There are also comic covers, weapons and mission challenges to unlock as you play.
The story is written by comics scribe Garth Ennis (Preacher, and, currently, The Punisher), and it is top notch. Like all of Ennis' work, it's funny, deep and interestingly violent (bordering on sick at times, but the creative take keeps it on this side of the line).
There have been comparisons to Max Payne. Though gameplay touches differ, there are definite similarities. The Punisher isn't quite as somber a story. It's important to note, however, that Max Payne was created with a lot of the Punisher's already existing story in mind. I think Max Payne (especially #2) may be a better polished game, but so far The Punisher is more fun.
Really, if you're even slightly curious, I can't recommend it enough. Not Game of the Year or anything, but a blast to play, well designed (I usually am impressed with Volition, so no suprise there), cleverly written, and just the right level of challenge. CGFE GO!