Stopwatch combat is intentionally linear and constrained, which could turn away some who enjoy the more expansive, free-wheeling style of Battlefield. Objectives always need to be completed in a deliberate order; first you fix the transport vehicle, then you escort it to the destination waypoint down the road, and only then can you take the EMP charges stored on the transport to the data center, where they are planted and detonated. Secondary objectives dot the landscape, and while they're purely optional, they can be toggled endlessly by both teams (lowering a access bridge, only to have the enemy team raise it back up). The combat and level design is immediately familiar to veteran ET players; in fact, the Chapel map is homage to the original Enemy Territory stage Gold Rush). Stopwatch is about choosing your moments, knowing when to push as a team, and realizing when to regroup or deploy a new strategy. Lane offense and defense replace the zone tactics reserved for larger Battlefield maps, with each player choosing (and hopefully sticking to) a specific job during each phase of a map.
While many aspects of Dirty Bomb's design are constrained (or dialed back when compared to Brink), teamwork mechanics are perhaps its most fluid component. The selectable mercenaries have their own specializations (Phoenix is a Medic, Bushwacker is an Engineer, etc.), but every player can do every job, and complete every objective. A Medic can revive teammates quicker, but I can still be revived by someone playing as Rhino the heavy weapons specialist. The same goes for repairing vehicles, planting bombs, and capturing waypoints. Mercenaries are very limited in their Loadout selections (a Medic cannot use a machine gun reserved for Assault-type mercs), so there is an appropriate amount of balance present in the team-forming equation.
Weapon and perk selections are limited to specific mercenaries, but Loadout cards do add some variety in the pre-match customization stage. You can enter a server with three Mercenaries on tap, each with a Loadout card selected. These Loadout cards have an aesthetic change in gun selection (a Medic will have access to several SMGs, but they are all behave similarly), while the perks (faster reloading, more ammo, etc.) are the real differentiators. These Loadout cards are found in crates, opened by keys, which is where Dirty Bomb's free-to-play strategy comes in. Similar to Counter-Strike: Global Offensive, and Team Fortress 2, Dirty Bomb's revenue generator is a crate and key system. This means there's no XP boosters to buy, and no perceivable "pay-to-win" strategy present within the game. A scrap system will eventually be added as well, allowing duplicate Loadout cards to be converted into keys. Based on how successful these systems have been for Valve, it's a step in right direction for Nexon and Splash Damage both -- a zero-barrier entryway for new or returning players, while leaving the long-term cash cow door wide open.
There are many FPS experiences that cater to the "Run and Gun" player, but Dirty Bomb is not one of them. Like its predecessors, the game has a sharp learning curve, and those not willing to put in the time or follow the plan will leave servers feeling rather frustrated. The teammate who keeps the transport vehicle up and running at all times is just as important as the front-line attacker who racks up 30 kills in a round. Time is the only true measure of success here, even if kills, KDR, and other stats are measured and displayed. Shooting from the hip is encouraged, as are hyper-accurate grenade placements, knowing when to disable certain objectives, and how to move about through the map.
If Dirty Bomb's open beta lives up to the benchmark established during the preview, then the asymmetrical shooter is back way in a big way, come 2015. One can only hope that the lack of polish in Brink's final retail form does not make a return in Dirty Bomb.