Essentially the engine is more modern, the graphics are nicer, and the simulation seems to be better. It is also hopefully a better base for newer mods.

I love CS1 but the engine is 8 years old and PC gamers in particular have been hitting the engines limits in multiple ways for years. There were also some fundamental design decisions which limited the scope of what could be done with the game going forward - it is definitely time for a sequel.

To be fair though, CS1 is going nowhere and has a massive amount of content available for it (including the massive free community content). It will probably take a couple of years before CS2 surpasses it. Although for Console gamers it'll probably quickly surpass what CS1 was and is able to offer.

• vastly improved road tools
• (seemingly) traffic AI comparable or even better than TM:PE
• seasons (!)
• Actually Useful Unique Buildings
• Vastly improved industry handling
• More Zoning, importantly mixed use and degrees of residential
• Better Custom Industries mechanic (not district based, expanding on the new base will allow for more engaging additions through DLC, Updates or Mods)
• Improved Outside interactions (ability to buy/sell electricity for example)
• Ability to create outside connections without mods
• Finer expansion planning via smaller squares (map size aside I think the squares being smaller is a good thing)
• Overhauled city expansion mechanic, you don't have to spam population to unlock new things and you don't automatically unlock everything. Instead you gain points via xp you get through multiple activity sources (you can level up a city solely by building streets for example). The points can then be spent on more advanced buildings of the basic unlocks (highways have to be "bought" using those points after unlocking roads, trains have to be "bought" after unlocking busses, etc.)

"What does this newly released game do that this other game (THAT HAS HAD EIGHT YEARS OF MODS AND EXPANSIONS) doesn't do?"

Keep you from asking stupid questions, for one. Just like every iteration of every heavily modded game ever. And in eight years you'll be asking the same stupid question about CS3.