If there are some criticisms, they're based around how you might perceive some of the mechanical systems of the game. How you feel about these things will come down to the nuances of taste and personal experience, but we think some people will be put off by them. One of these issues is the amount of time you spend dead. Because of the spawn-wave system you'll be waiting for anywhere between two and 25 seconds to be respawned. For such a fast-paced game that seems a long time to be spent lying prone on the battlefield. Death is routine too, especially as the game has a potent mix of automatic and precision weaponry - you're worrying about snipers and close-quarters spammers at the same time, which can feel like a nightmare when things really start to kick off.
The other problem, which isn't one that can be addressed in any way, is how you feel about asymmetric combat as a whole. Because one side is always defending a series of objectives they are, in some sense, only staving off the inevitable. They are, by default, fighting a retreat. In a game where the objectives are symmetrical there's always the chance you can come back from the bad position to win the game, capping the flags, holding the objectives for those vital seconds, and so on. In ETQW the best defenders can hope for is to hold on until the counter runs out. Something about that doesn't sit quite right with us.
Ultimately these points do little to detract from the overall achievement of ETQW. It's a game with relentless pace, but where flanking, careful sniping, and support actions are all a part of a successful cooperative experience. Accomplishing objectives is how you get XP for the campaign unlocks, and it's all skewed towards teamwork. Even selfish play should end up rewarding the team as a whole. In years to come all multiplayer games will want to do this.