Explosives never fail to provide fun. If exploded directly on someone, they attack the under armor, which is usually the thinnest; they also do quad damage vs. large units. Blast usually weakens by 10 per tile, but eg. Fire inflicts full damage within the whole area.
>Launched. These use some kind of a launcher and explode on contact.
>Thrown. Much like the former but require no launcher.
>Fused. They explode after a set number of half-turns (0 is after your current turn, 1 is after the next enemy turn, 2 is after your next turn etc). Prime, then Throw or drop.
>Proximity. When primed, they explode when someone enters or leaves a 1-tile radius.