Tip: Take advantage of easy to install Patches in your hack. The No More Sprite Tile Limits or SA-1 patches should be considered if you're encountering glitches where Mario and/or sprites are turning invisible.
This patch allows you to make explosion destroy specified blocks upon having touched them, as shown in this video. More information in the readme and .asm file.
Credit not needed. Moderator's note: It doesn't obey the Acts Like settings, but it's easy enough to expand the table if you need more explodable blocks.