Quick review since I have to get going:
Watched it. My feeling is they did a heck of a job partially because this is the inverse of The Room. The Room is 90% terrible dialogue and 10% terrible sex scenes. Gymkata is 90% cheesy action with 10% dialogue. Seriously, I think there was a 20 minute sequence in the final act with no dialogue at all, just Kurt running around doing gymnastic routines on pommel horses in the middle of town squares while kicking people (Gymkata!). So the guys had to make comments on the cheesy action, but came up with entertaining stuff.
There were a few points where someone would throw out a zinger and it felt like genuine, spontaineous laughter from the others. Usually I was laughing along with it. They manage one running gag early on with the Princess' 'interesting backstory' being her mother was Indonesian... and that's it. But it's so stupid the guys constantly bring it up and it works. Kurt is the inverse of Tommy W since he doesn't say much. It's almost like the producers realized he had no acting skill and thus kept it minimal so there wasn't a ton of dialogue to rag on. Terrible largely non-sensical actions scenes, and a town literally filled with mentally ill people (like a homicidal leper colony), also litter this piece.
I would rate it well above things like Kill and Kill Again or last year's Street Fighter. I recommend it. Not a classic like ROTOR, but definitely worth owning in my opinion.
And yes, I was totally with the guys on 'This was based on an actual novel?' when it was revealed at the end.