I played the campaign through last two days.
The gameplay of Dragon Rising is decently realistic and challenging, you can die from a single shot if hit in the face, you can get wounded and need assistance by a medic, vehicles have fairly realistic damage (comparable to Arma 2), and shooting is somewhat off, I can't pinpoint what's wrong with it, but it's somewhat unresponsive and there is very limited amount of weapons. There are vehicles from trucks and cars, through light armor to tanks (although only one tank for Americans and one for Chinese), plus two helicopters. However, multiplayer is dead - I don't mean the lack of player, but servers are completely down, so you can only play singleplayer campaign and missions, which is essentially infantry gameplay. Except hummer and enemy's unarmored counterpart, you rarely get to drive anything else.
Missions are rather mediocre, however, quite challenging. You can traverse the whole map any time, so they are open-ended and this allows creative attempts to reach the goal, however, the game still gives you quest marker all the time for 'recommended' route. Sometimes it can be annoying and confusing. Moreover, often you have to get to that 'recommended route' anyway to trigger a script to continue the mission. What's worse, AI is braindead, it often stands in place and allows you to shoot them one by one, without any maneouvers whatsoever, even dumb ones. This includes the highest difficulty. It is also able to see you through grass though.
Unfortunately, despite the ability to traverse the whole map at any moment (assuming you avoid enemies or kill them) there is no point in travelling because the map is extremely void and boring. Not only it pales in comparison to Arma 3 or 2 or even 1, it is also far inferior to the original Operation Flashpoint, because the entire map is made of only terrain, trees, roads and single buildings. The only exception is a small airport. That's right, there's not a single town or even a proper village on the entire island! The largest conglomeration of buildings pretending to be a village contains less than 10 buildings. It's as if someone generated an island and put some trees and single buildings as a placeholder, but it ended up in the final version of the game. I can't even remember when I saw such an empty map last time. Even Tajikistan in Arma 2: Operation Arrowhead - a territory that is just a desert - had small towns and other points of interest. Here is nothing at all.
Add to it an annoying UI, though a bit less annoying on highest difficulty, a tunnel vision FOV and rather awkward controls and you end up with a below average military sim. It's playable, it's severely inferior to any Arma or original OFP, but excluding multiplayer-only there are no other military sims so... I don't really recommend it, but if you can get it for almost free and have nothing else to play then it might not be a waste of time. Nonetheless, if you don't then you don't lose anything of value either.
By the way, I am in love with the main theme music track, it's unusual, serene, and it's great.