Raging Pigs Free is a free puzzle game featuring pigs and birds. You control the pig, and your only goal is to kill all the birds in each level. This sounds are very simple, but the game is actually kind of hard. I struggled a bit to complete the first level, mainly because I was rushing through it.
You control the pig with the arrow keys. You can move left, right and jump. There are also crates that you can use to squash birds. When you want to move a crate, you need to hold the shift key. To kill a bird, you jump and fall over it. If the bird hits you on the head, you lose. So the key is to jump when you are next to them and move while you are in mid-air to fall on them and kill them.
In the first level, you can simply wait for the birds to come down in groups and kill them one by one. In the second level, you have crates at your disposal. You can push those to kill birds, but if a crate falls on you, you are dead.
The game features 28 different levels with different challenges, which should keep you playing for hours.
In short, Raging Pigs Free is a nice time-killer for you to have installed on your Mac. It is easy to play but challenging, and absolutely free.