ZDoom

I thought maybe you could make a sector, and then somewhere make a dummy sector, to fill that in. When an explosive hits the destructible part, it disappears, spawns debris things, and the dummy sector no longer blocks the way. This would help give the players more to explore, and allow more creativity for mappers.

Isaacjedi5 wrote:I thought maybe you could make a sector, and then somewhere make a dummy sector, to fill that in. When an explosive hits the destructible part, it disappears, spawns debris things, and the dummy sector no longer blocks the way. This would help give the players more to explore, and allow more creativity for mappers.

... so just like Duke Nukem 3D... Good luck getting this in.

Simple way to make destroyable walls without needing to use ACS:
Make an invisible shootable non-solid actor, and place it near the place you want the wall to explode. (make sure the actor can only be destroyed by explosive weapons).

Make the wall already destroyed, then make a dummy wall that has only 1 block of thickness, and give it a tag. When the actor gets destroyed, on his death animation spawn debris. Make the actor special lower/raise the dummy wall.

I did it on this map. Check it out.
http://www.doomworld.com/idgames/index.php?id=16991

If you ARE okay with using ACS, then the answer is pretty straight-forward and you only need 30 seconds, a script, a line, and some map spots:
Alternatively: