Where Skylines gets really interesting is in how it lets you specialise or diversify your city through the use of districts. Once painted onto a part of your city, districts allow you to apply special laws and regulations. In one instance, I noticed a huge amount of traffic trying to squeeze through a tiny roundabout in a residential area, so I turned that space into a district and designated it a low-traffic zone. This forced these shortcut-abusing drivers to take a slightly longer route which had much wider roads, solving the congestion problem.
Districts are especially useful when combined with specialised industries. Early on I spotted a plot adjacent to my starting area that consisted primarily of land suitable for farming. So I purchased the plot, created a small industrial sector, and dedicated it to agrarian industry by using the appropriate district setting. This farming district also had the benefit of being enormously pretty, all golden wheat-fields and lowing cows. As my city grew, I adopted this tactic twice more to exploit other surrounding natural resources, namely oil and ore (which admittedly were less pretty, but who cares when there's money to be made?). My city expanded almost naturally around those areas, as I needed to build nearby residential zones to provide a workforce for those industries, construct services to serve the new residents, and connect all the far-flung districts together with transport networks.
Unfortunately, Colossal Order have missed a trick when it comes to the districts. I noticed this due to a flaw in the game which became increasingly apparent as my city grew. Basically, dead people started piling up in residential areas, despite the fact that I had built several cemeteries and crematoriums around the city, and statistically had plenty of space for bodies to be disposed of. Stupid humans and their mortality, ruining my lovely city!
Initially I suspected this to be a traffic issue. Skylines places strong emphasis on a good transportation system. Your commercial hub will quickly suffer if people can't get to it easily. Ideally you need at least two forms of transportation heading to every major area (pro-tip, build metros). Moreover, if you aren't careful about connecting up your road network, ensuring there are plenty of alternate routes for getting around, you'll quickly run into problems.
Yet regarding my surplus of corpses, there was no obvious congestion. Instead it seemed more like these services were not prioritising proximity. The district mechanic would offer an easy solution if it allowed you to restrict services to working within a certain district. But as far as I can see, it doesn't, and that's as shame.
Or it could simply be the case that as a city becomes bigger, people dead and alive inevitably start falling through the cracks. Certainly I noticed that as I built more schools, high-schools and universities, the manufacturing and agrarian industries began to flounder, as there was no uneducated workforce willing to perform the manual labour those industries required. This left me with an interesting moral dilemma. Should I deliberately reduce education availability in the city to support those industries? Or should I put the remaining farmers and manufacturers out on their ears in favour of more commercial and office space?
In the end I couldn't bring myself to do either, and instead periodically bulldozed the abandoned buildings of failed farmers and misguided manufacturers. Incidentally, having to manually remove individual buildings in a sizeable city is incredibly fiddly. It would make more sense to be able to build a demolition service once your city reaches a certain size, and let the AI take care of it.
Aside from the general unwieldiness of managing a large city, which frankly is to be expected anyway, my complaints about Skylines are few. The simulation seems to be structurally sound and enjoyably detailed. Watching trains pull in and out of stations and fire engines race toward a blazing building is gently gratifying. I even saw two tiny undertakers carrying a coffin out of a house toward their hearse parked outside. When it comes to things like money management, Skylines isn't the deepest simulation in the world. I just found the taxation sweet-spot (12% for everything), acquired a couple of loans early on, and after an hour or so was never short of money again.
In my opinion that's absolutely fine. Frankly my finances are terrifying enough in real life. I really don't want to have to worry about them in a videogame too. No doubt some bright spark will create a mod for more complex economics, given that Skylines' community is already bustling. I simply wanted to build a great big city, and watch all its moving parts tick and whirr for a while. Skylines lets you do precisely that with minimal restrictions, plentiful options, an impressive eye for detail and just the right amount of direction. Because of all that, it gets a big thumbs up.