While going through the stage installations files, I found a walle include file at Stage-3.2.0-Source/worlds/walle.inc.
Marrying walle.inc file with the 'usual' simple.world, simple.cfg and sick.inc files I got wall-e to move around in the 'caves' environment !
Somehow this appealed to the child in me ! :)
The following video is by talk2aswin;