[Answer] 1. Number 8 is the free version of the number 1 paid app. It's a game which seems kind of bizarre - in it, you launch different types of birds as projectiles at green pigs.

Step 1 : Introduction to the question "1. Number 8 is the free version of the number 1 paid app. It's a game which seems kind of bizarre - in it, you launch different types of birds as projectiles at green pigs."

...1. Slaughterhouse Free 2. Bird Catapult Free 3. Angry Birds Free 4. Go Get Some Pork! Free Developed by Rovio Entertainment Ltd, the Angry Birds app franchise has enjoyed remarkable success. The players launches birds with different abilities and powers at the green pigs' structures, attempting to essentially crush the pigs into death.