The Spooky Hamoween update is live on Steam:

http://store.steampowered.com/app/575590/

– New Hamoween event!
– New character select screen
– Added 6 spooky pig skins
– Added 1 new song
– Added 1 new background
– Fixed easy mode for 2 players
– Fixed specific clouds that never spawned
– Modified gift price for pigs from 50 to 35. More pigs, so its easier to get them.
– Modified pig unlocking screen.

The Spooky Hamoween Trailer:

For more information on Balloon Popping Pigs:

https://drinkingnails.com/2017/01/17/balloon-popping-pigs/

Steam Version:
You can buy it for around a dollar in most currencies here:
http://store.steampowered.com/app/575590

Free Android Version:
Otherwise, the free version is available on Android here:
https://play.google.com/store/apps/details?id=com.bonebender.balloonbreaker&hl=en