To make a univeral shoot through walls- that will work on all maps and penetrate all objects- you need a debugger- like ollydbg; and a bit of patience.
One by one- go through the export functions in game.dll and logs.dll; paying close attention to the COL_ prefixed functions (which stand for collision- obviously). In each function, insert JMP's or NOP's over code to force the procedure to exit as quickly as possible (eg. hit the RETN x86b instruction; and hence not calculate collision information).
It's not the easiest hack in the world to make; but it's definately one of the most rewarding.
Subsky