I'd like to mention an issue with the Snowman Cannon.
Currently, there are two rough categories of launcher: Those that use the special properties of their ammunition, and those that don't. The Grenade Launcher, Rocket Launcher, Proximity Mine Launcher, and Snowman Cannon fall under this first category. The Electrosphere Launcher, Celebration, and Celebration Mk2 fall under the second category, overwriting all properties except damage (with the exception of the Celebration Mk2 in regards to tile destruction).
However, despite inheriting most properties of its ammunition, the Snowman Cannon has one strange exception. Currently, when used with Cluster Rocket I or Cluster Rocket II as ammunition, the Snowman Cannon's rockets create the usual Cluster Rocket shrapnel, but unlike with the Grenade Launcher, Rocket Launcher, or Proximity Mine Launcher, the shrapnel explosions do not deal any damage.
My question is this: If the Snowman Cannon is not intended to work with Cluster Rocket I and Cluster Rocket II, why should it create any secondary explosions at all? I can't help but think this must be an oversight. Either the secondary explosions should cause damage, or there shouldn't be any at all.
I also find it strange that the Celebration Mk2 is able to inherit tile-destruction properties from its ammunition, and its predecessor cannot. It seems like a property that the Celebration (and even the Electrosphere Launcher) could validly inherit, as there is nothing to lose by allowing them to benefit from the even-numbered rocket variations.