The below has been tested with Ubuntu 12.04. Start the command line (started by running Accessories → Terminal) and enter in the following commands.

You will first need to install dependencies and needed programs by running:

sudo apt-get install build-essential subversion libsdl-dev libsdl-mixer1.2-dev liballegro-dev g++ libsqlite3-dev libjpeg-dev

You will then need to download the source code and assets to your computer. Move to the directory where you want the game installed and run the following commands:

svn co ire

(“ire” is the name of the game's engine)

To actually compile the game into a playable form, enter in these commands:

cd ire/engine
make -fmakefile.lin

And now to run the game, enter:

cd ..
./ire-engine -window

(remove the ”-window” argument for full screen)

Have fun!

By the way, if you want to clean up an build, just go to the engine folder and enter:

make -fmakefile.lin clean

If you've downloaded the code but want to update it to the latest version, go to the ire folder and enter:

svn update

Then just build the code again.

Finally, let's say you want to go beyond simply compiling code… and actually contribute!
Well, if you've made changes that improve or fix the game, and want to send them to us, just navigate to the trunk folder and type in:

svn diff > ~/awesome_fix.diff

And send us the diff file that gets created.

If you want commit access (so you can change the engine whenever you want), just talk to us first and we'll see what we can work out. It'll help if you've already sent us a few diff files though.