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.

http://www.openttd.org/en/download-stable

I'm fairly certain they're pretty much complete replacements now, but I haven't been able to get the music pack working on Arch yet.

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.

You know, I've actually spent the hours leading up to the SimCity launch coding a simple clone.

Here's a link http://www.browserpolis.com/, you need a webgl enabled browser though.

And a screenshot (http://imgur.com/4ixB2lO) in case you can't see anything.

Works here in Firefox 19.0 and Chromium 24.0.1312.56 on 64-bit Linux.

I didn't see the GitHub link in Firefox, though, so in case anybody missed it here it is: https://github.com/dreamingofelectricsheep/browserpolis.

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.