Full disclosure: I've been a fan of 5SF for years and even bought tickets to the world premiere at the LA Film fest so I'm probably a fanboy.
There are a plethora of horror comedies out there, and many self aware entries into the genre will poke fun at their own tropes, but never before like this. The best summary of DBPM3 I could give would be Friday the 13th mixed with Airplane mixed with the volleyball scene from Top Gun. The film has one of the highest jokes per minute rate of any I've ever seen: any duds or misses are swiftly forgotten when another joke is laid out less than 10 seconds later. It grabs a hold of your funny bone and mercilessly throttles it, I felt physically exhausted by the end.
Even though it is a satire of 80's slashers, most of the jokes are timeless, and don't require extensive knowledge of the genre/time period to understand (and good thing too, I imagine the target audience was still in diapers during the 80's). It attempts to recreate the poor quality film making of low budget slashers, and largely succeeds, to the point where I couldn't tell which mistakes were intentional (i imagine most of them)
The only stumbling block for me was the side plot involving Officer Sminkle. Although funny at times, it seemed to drag on, and was only tangentially related to the plot. For me it never seemed to join cohesively with the action at the frat.
My advice? Get a group of friends and a case of beer before viewing this movie. It is strong on its own merits, but seems to have been created with group viewing in mind.