Nice game!
But there's this bug, hope you read your reviews...
I've noticed that when buying a new penguin, you don't 'really' get charged for it. For instance I saved up 5000 gold for my 4th penguin, and I still had 5000 gold. Then I saved up 20000 gold for the 5th penguin, and had 20000 gold still! The money only got deducted AFTER I bought an upgrade for one of them. I'm not sure it's supposed to work like that, but otherwise it's a fun, original game :)