Not short if you play extreme difficulty but then the game become utterly unforgiving and furstrating!
Take cover is a lie! It is utterly "broken" and you have to constantly worry about AI shoot you through the cover in extreme mode. When you see people talking about the best way to beat extreme mode is not to use cover system you know the basic fundation of the game has problems and where the hell is the QA of IO interactive and do they have any QA guy seriously?
Blind fire is more accurate than micro-aiming
Don't try to aim in this game because you fill soon find out some times blind fire will kill enemy faster than your aiming skill no matter you are a CS vertan or legendary master chief in other games. Still I question the QA from IO: when people using blind fire more than their micro aiming something is obviously wrong witht the weapon and aiming system and they will make the game not fun and rewarding to play. Guess you learnt that lesson twice already.
Above are the two most drastic failure I could think of to this game, I am OK with the shaky camera mode but it should be included in the extreme mode as an optional setting. You can't depends on the unique shaky camera to make a game enjoyable, afterall deep under its skin the control mechanic and game play value(rewarding, non-liner, skill, story, fluence multiplay, etc) decide the fundamental rating of a game.
if you can over come the frustration and anoying control and camera of this game then it's actually worth trying, I actually felt the game was not that bad when I played the level where the government soilder first appear in the game. Sadly the only difference of different AI in the game is what they looks like and the weapon they use, with the black special force as an exception because they are hard to kill.
Dog days offers fun street gun fight and the gun fight on the street is really fun. (wish if they could improve the aiming system better). It is not short as the hype said 3 hours if you play extreme but I guess few people play extreme afterall. Some basic fundamental element of the game is brokem and feel not finished or polished enough. I give it a 7.5 to general gamers and 5 to players who want to play extreme mode because the frustratingyou will get isn't really worth the rewarding feeling you get after you beat extreme.