EDIT: If you could also provide me some GFX, as well as test out the P_ models (both plain and shield ones), that'd make me happy. I'm always open to accepting contributions from others, as well as collaborations.
This is a great concept, we need more original stuff like this in the section.
While the current animations are not at all bad, I'd love to see something more. For example you can change the pullpin animation to pull out the carrot from the snowman. Or you can use the animations from Birdhouse's BD-11 Grenade pack to flick the hat and make it look like there was a button in there that was pressed to activate the bomb.
Actually, there are various possibilities for custom pullpin animations here. The twig could be bent or one/many of the buttons on the snowman can be pressed for example.
Another room for improvement is custom sprites, for the smoke and HE grenades. Can have a candy pop custom explosion effect to go with this, or maybe some blue colored explosion like this one. As for the smoke effect, can go with multiple white snowflakes.
This would also go great with some christmas-themed arms skin like Santa arms for example, although I couldn't find any in the arms section. There are a few red colored gloves in there that might fit though.
On a final note, missing the P models, sprites and GFX since they provide a much better experience even though they take effort to make.