Playing Payday 2 offline is only advisable as a learning tool, used to get a basic understanding of the maps and jobs on Crime.net. Skill points (used for purchasing special abilities and attributes) and cash can be accrued offline, but it amounts to chump change compared to what's on offer in the big-time online heists. Besides this, the offline AI isn't up to par. Although your teammates won't fare too badly in shootouts, they're woeful at mission-specific tasks. For instance, they won't pick up loot - leaving you to run back into the nightclub warzone you only just made it out of to retrieve further bags. This won't happen online as everyone's in it together.
Online play boasts a much greater selection of jobs to drop in/drop out of. You must be quick in deciding which to take as they're only available for moments at a time. Selecting the right job to fit your level of experience and gear is of paramount importance: join a high-level team without the right tools and you'll likely be the cause of failure. It's most satisfying to stumble upon a team who're at a similar level, run a few jobs as a unit and level up together. A definite sense of camaraderie builds up the more times you work with the same crew.
Some jobs take place in one section over a single day, whereas others are drawn out over multiple days. For instance, you may be tasked with escorting a drugs shipment incrementally through hostile territory - with your team penalised for any losses incurred en route. 'Professional' jobs offer high risk and high reward with the trade-off being the termination of the contract and nothing gained should the job go awry. The jobs often take unexpected twists, as your scheduled getaway is forced to exit under enemy fire, leaving your team to defend itself in a hail of bullets as your dispatcher figures out an alternative escape. It's these moments of uncertainty where your team's combined perks and equipment will figure heavily.
During my hours of online play, I found the most effective teams were not only kitted out with a decent mix of health kits and ammunition packs, but knew the maps well enough to know where to deploy them (they can't be moved once placed). Further to this, the inclusion of heavier firepower is a must for harder jobs in order to be able to take on the armoured SWAT teams and commandos sent in to stop you. There's the option to approach jobs with a stealth-based approach, but every time this was attempted it soon descended into something out of Reservoir Dogs.
Once your health hits zero, you're downed (but can still fire your sidearm for a short time, ala Modern Warfare) and must be assisted back up by a teammate or end up in custody. A choice must sometimes be made on the fly between reviving teammates under fire or trying to push forward and complete the job's objectives with a man down.
As long as at least one other teammate is still in the game, while in custody you have a chance of being released via negotiations made by your dispatcher, besides having your freedom traded for that of a civilian hostage (if your team has taken any). Luckily, if just one player successfully makes it through to the end of the job, it's deemed a success and everyone reaps the benefits. This lends the game a massive amount of tension, as a formerly robust squad is gradually whittled away, leaving just one player powered on to criminal glory by the collective will of the others.
It's easy to get completely sucked into the game once a job's underway - I often worried about the hard time I'd have to do should I have fallen and be shot and arrested by the police. Stumbling down a road, lopsided due to the sports bag full of cash on my back while taking fire, is intensely cinematic and utterly tense.
Playing Payday 2 online is easily as addictive and enjoyable as the Modern Warfare series' multiplayer, and with a year of DLC in the pipeline, there appears to be enough to keep it fresh. Hopefully some future patches will address certain gameplay shortcomings, but you very much get the sense that this is a sturdy base for Overkill to build upon in the coming months.