Condensed explosives are a derivative of conventional TNT. It only has a one tick fuse and therefore explodes immediately when ignited. It's neat and easy to make, is used in various recipes and has multiple uses in ICBM. Combine this with the Glass Pressure Plate and you get an ultra-stealthy instantaneous land mine! The damage and explosion radius is less than a normal TNT. As such, it will take a few of them to kill a target. The short-fused explosive can be detonated by a Remote Detonator and will also drop 100% of all blocks it destroys. This makes the short-fused explosive good for mining and breaching (like C4).
Missile form of the above Explosive is notably called a conventional missile.