Collapsable Sprites can be destroyed by explosives. The collapsable bridges in the game which appear to be "truly 3D" are actually made up of sprites.

To make a wall-aligned or floor-aligned sprite 'collapsable', assign it a unique Hi-Tag. Any collapsable sprites sharing the same unique Hi-Tag will collapse together as a unit. Face-aligned sprites cannot be defined as collapsable. Collapsable sprites will automatically be set as blocked and hittable in-game.

A Collapsable Bridge is constructed with a floor-aligned sprite, resized to cover a gap. Make sure it is two-sided (use the 1 key if it isn't). Give the bridge sprite a unique Hi-Tag to make it collapsable. To make the bridge seem truly 3D, add floor-aligned and wall-aligned sprites to the bottom and sides of it, and make sure all of the sprites are one-sided instead (use the 1 key if they aren't). Give all of the bridge sprites the same unique Hi-Tag (effectively a Channel) to make the entire 3D bridge collapsable.

Notes:

• Ugly graphical glitches can occur with 3D sprite objects. Sprites will often show through each other when they shouldn't be visible. To avoid this, make sure all of the sprites are one-sided (with the 1 key). This way, all of the hidden sides (which caused the graphical glitches), will be completely invisible and will not cause problems.
• Graphically speaking, sprite clipping is determined from the center of a sprite. The larger a sprite is, the greater the chance that it will have graphical clipping issues (i.e. other sprites will be more likely to show through it). When constructing a large object from sprites, use a series of smaller sprites rather than just a few large ones.
• Check the "References - Compatibility Listings" section for the complete list of incompatible objects (since most of them are compatible).