Changing face of the PLA. I'm surprised, they didn't have a major parade in front of Tianammen Square with marching bands and so on. You know, the typical Communist display that North Korea still practices, and sometimes the post Cold War Russia would do occasionally.
How the PLA celebrated its birthday.
No display of parading tanks, armored vehicles, the requisite TELs carrying akk sorts of missiles and formations of planes flying overhead.
Rather this demonstration is rather small scale. Also another important fact is that they're celebrating in a naval base, not army or airforce. Again that is a signal and a message itself of the navy's growing importance, since such celebrations are never held in a naval base before.
Besides that, the PLA celebrated its 80th in a very nontraditional way---by having a major exhibit that is akin to an arms show. From what I heard, the exhibit was certainly popular.