openttd is a strategy game based on transport tycoon deluxe. It is a rewrite under GPL licence and recently the project created its own data replacement, so that you no longer need to use data files from old transport tycoon game (which are non-free).
I was planning to post an extension but the procedure is fairly simple to build one on your own. And i still have a few doubts about a couple of things.
How to make the extension :
i took prebuilt binaries for i686.
http://binaries.openttd.org/releases/1.1.1/openttd-1.1.1-linux-generic-i686.tar.gzand graphics data
http://binaries.openttd.org/extra/opengfx/0.3.4/opengfx-0.3.4-all.zipunpack binaries somewhere, and the files from opengfx into data/ subdirectory. and you can package it using standard practices.
dependencies :
libpng
sdl
fontconfig
icu
I've tested this game and it works with necessary packages off tce repository.
The binaries provided don't really care about the directory you put them in. I put it into /usr/local/openttd and it worked. It also worked from home directory.
The problem - game offers online updates for game data (not the binaries) and addons (ai, maps, graphic packs, music). Also, on first run it will complain about missing music and sound packs, which can be downloaded (but are not required to play).
Any downloaded addon data is stored in ~/.openttd. You can also add it into games data/ directory and it will work too. I am not sure whether extension should package music and sfx, or should it be offered as a download from the game itself?
game + opengfx is the absolute minimum to run it. rest can be downloaded through the game's extension manager. so i am unsure what to include in the extension, and what to offer as a download.