I just noticed in here that this tile is full, is that your limit or can you expand further?
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That is the limit, but you then construct a new city on another tile in the same region.
What they went for is cities working together.
An example is your town hall have limited upgrades, so you will never be able to unlock everything with one city, however upgrades are region based, so all unlocks within one region is shared among all cities.
So if someone upgraded their town hall with the education department, you do not need to upgrade yours with the same, since you already share the benefits.
There is also what's called 'great works' within a region. It is a tile where a unique structure is built.
This can be anything from a large international airport, to a space shuttle launch pad. all cities need to work together and have several specializations to provide all the materials to complete a great works.
So. If you want to build massive cities and that's all, rather stick with skylines.
This is a city builder / manager. Smaller tile size, but a lot more too it than just building.
I still enjoy it way more than Skylines.
Normally by now I would be bored if I was playing skylines
Edit:
There is actually still a lot of room on that tile.
It looks deceptive at a glance, but once you see how it works there is ample room.
Like I mentioned previously. you do not need to build several police stations, school, clinics etc. You expand the ones you already have. saves a lot of room