This is no longer relevant, WarMUX on Android runs with fullres graphical resources; sound was indeed resampled, but not commited

Images

The images should be halved (in both dimensions); there doesn't seem to be a need to convert from RGBA to another format.

Having a script to do the job would be good, though we must find whether we should process the regular data or from the source. The script would probably use imagemagick.

Sounds

All sounds are in ogg format, often 44.1KHz stereo. They should be resampled to 22.05KHz mono and also at "-V 2" quality equivalent (~96Kbps).
This is also an obvious easy task for a (shell) script, probably using oggenc

XML

Here is a list of files that probably need editing. I have indicated for each entity to be edited, their parents and the properties to edit.
This probably require a more advanced scripting language than shell: finding the entities, and editing the properties is not straight-forward.

• body/movements.xml: movement={ collision_rect={left, right, top, bottom} , frame={ member={dx, dy} } }
• body/skeletons.xml: sprite={ anchor={dx, dy} , attached={dx, dy}
• cursors.xml: mouse_cursor={x, y}
• graphism.xml: sprite={ image={ grid={pos, size, array} } }
• weapons.xml: sprite={ image={ grid={pos, size, array} } }
  

Code

Menus

Some menus hardcode some sizes for their elements. For those sizes, maybe writing size / DIVISOR (1 for regular targets, 2 for small screens).

Objects

Some of their properties are also dependent on the world size: in particular speed and such things should be normalizd (/DIVISOR²)