4. OpenTTD -- https://secure.openttd.org/www/en/. Same as above but requires Transport Tycoon Deluxe resources to run and might be closer to it in terms of mechanics.
[1] This is what I was half-hoping to see when I clicked the link. It would be really cool, and possibly profitable, for someone to quickly prototype one in HTML 5 in response to the SimCity 2013 fiasco.
Just thought I'd point out that Openttd doesn't require the original resources to run anymore. There are OpenGFX, SFX and MSX packs to replace any proprietary content.
Another note, once you get the base graphics working start the game, go to downloadable content and download the zBase graphic pack, which is around 207MB. Those are vastly superior to the OpenGFX pack, and gives OpenTTD a very polished and modern look.
Say, how do you plan to add terrain height to the game? At a glance it seems that your engine wasn't built with it in mind. It might warrant a total rewrite to put it in as early as possible since it's such a major feature of how SimCity-type games play and (especially) look.
Edit: I was thinking more about how you'd manage placing Bezier roads over an uneven heightmap.
Heightmap based 3d would be very simple to add via something like f(x, y) -> x, y, heightmap(x, y). The city building genre is essentially "2.5D", as the gameplay itself is purely 2d with the third dimension existing solely in the presentation layer.
Edit: As for the roads on uneven terrain, I'm thinking about deriving z coordinate from another 2d Bezier curve traced along 't' of the road. Control points could be derived from a convex polygon obtained via the road/heightmap intersection.
1. Micropolis -- https://code.google.com/p/micropolis/. This game is based on the source code of the original SimCity released under GNU GPL 3.0. Concincidentally, there's an ongoing effort to produce an HTML 5 port at https://code.google.com/p/microwebopolis/.
2. LinCity-NG -- http://sourceforge.net/projects/lincity-ng.berlios/. Looks and plays similar to SimCity 3000.
3. Simutrans -- http://www.simutrans.com/en/. This one is inspired by Transport Tycoon.
4. OpenTTD -- https://secure.openttd.org/www/en/. Same as above but requires Transport Tycoon Deluxe resources to run and might be closer to it in terms of mechanics.
[1] This is what I was half-hoping to see when I clicked the link. It would be really cool, and possibly profitable, for someone to quickly prototype one in HTML 5 in response to the SimCity 2013 fiasco.