Buy it on: Mac App Store
Price: Free (offers in-app purchases)
This Bubble Bobble-esque bubble shooter puzzle game has been out for Mac since 2011 and is compatible with machines running Mac OS 10.6 (Snow Leopard) and up. Developed by Spooky House Studios, the music has groovy retro twists. Also, as you can see from the screenshot below, the Mac version lets you increase or decrease the transparency of the window, meaning that theoretically, you can do you your work running a text editor or spreadsheet in the background and play at the same time!
Free (offers In-App Purchases) and available in the Mac App Store.