If you have never watched this do so:
http://www.youtube.com/watch?v=Z1iaa04rCf0
In order of the events I saw:
1. Bad finning technique for an overhead.
2. Buddies seemed a little far from each other if diving as true buddies.
3. Entered overhead with NO GUIDELINE, and silted it up on the way in. Very fortunate that this was sandy silt and settled quickly.
4. 1st diver makes light motions once inside that look like what a cave/tech diver would see as an emergency, I guess this was his way to signal come on in.
5. 2nd diver appeared to motion to turn the dive and get out of the overhead on more than one occasion, no response from the lead diver, showing lack of training or knowledge for the type of diving.
6. Definitely a cavern dive, appeared to get into the cave zone too from what I could see.
6. Gear probably missing: Longhose, backup lights, redundant air or H-valve, reels.
7. Way to much touch feely on the corals.
Training level from what I saw needed to be minimum cavern, probably cave.
Pre-dive brief needed to include the plan to go into the cave, 2nd diver was clearly not expecting it and didn't seem comfy with it (smart).
Gear was missing for this type of dive.
This looks to me like one of the classic Rec diver doing the wrong thing that can quickly go south and get you killed scenarios.
You asked so there is my humble critique.
Then again, maybe the video didn't give me the whole picture.