PK:HaD is live now. Downloading it at the moment.
I had a look at the beta, and it looked very similar to the original game. Or, the first level did anyway, that's all I played. Of course, the first level is very dark, and far from the visually most impressive level. There also was no videos included, so no idea if they updated the (pretty crap, even for the time) visuals and animations there.
The painkiller weapon (the spinning scythe thing) wasn't present in the game anymore and was replaced with a new weapon that while more powerful (or so it felt anyway), it was no longer possible to juggle enemies for sport (and bonus gold!) So, a give and a take in all. I'm uncertain of the rationale behind changing the iconic melee weapon, I'm kind of like, if it ain't broke, don't fix it. And the PK wasn't broke, IMO.
...And here's an open invitation to Davros to come into the thread again to remark that the entirety of the original PK game wasn't broke, so no need to fix/change it...