[Side note: There's also a built-in mod that allows you to bypass these gates entirely, or give yourself infinite money, if you'd rather just be creative.]
The one downside is having to re-plan your city every few hours. The most disruptive additions are public transit-related, as you demolish buildings to make space for metro stations.
Highways can be equally hellish. While they're available pretty much from the beginning, they're priced out of your budget. Trying to figure out what to demolish so you can run a highway down the center of the city can be a frustrating and tedious experience.
But you can do it! And even more fascinating, you can affect what's already on the map. As mentioned, you'll gradually expand not just your city but the available map space for your city. You start with a single grid of 2 kilometers by 2 kilometers, and the map as a whole is a 5x5 grid of these squares (so 10 kilometers by 10 kilometers total). You're allowed to take over nine squares total, with the only requirement being that they connect in some way. (Of course, there's already a mod on Steam Workshop that unlocks all 25 tiles for your use.)
So that highway funneling civilians into your city? It might look like background decoration when you start, but it's a fully functioning piece of your city. Or, at least, it can be--provided you take over that grid square.
One feature I did miss is terraforming. At the moment, maps are maps. You can somewhat affect the course of rivers by building a hydroelectric dam, but you're not going to just fill that river in or stand up next to a mountain and chop it down with the edge of your hand.
In fact, the water/wind simulation as a whole seems less important than Colossal Order made it out to be ahead of release. Perhaps it's more of an issue if there's less water on a map, but my city had more than enough water to draw on. All I had to do was remember to set my water pumps upstream from my sewage outlets, and I was golden.
The water physics are excellent, but I never really had a moment of "Oh damn" while playing either. I'd love to see the feature expanded to introduce droughts or floods, for instance--ones that aren't necessarily made just by your own stupidity.
Building with ease
Which I guess brings us to the biggest problem with Cities: Skylines--it's pretty easy. It took me about eight hours to get to what I'd call the "end game," a.k.a. I've got millions of dollars, my budget is stable, my support buildings (fire departments, police, hospitals, etc.) are all in place, and I'm adding entire districts onto my city.
Sign up for CIO Asia eNewsletters.