A simple game that is very addictive.
The set up for this game is roughly the same every level, you have a catapult with which to hurl birds at pigs. The difficulty come in that the pigs have built themselves houses out of a variety of materials. Knock down the barrier and kill the pigs to win.
With limited birds to throw and increasing barriers the game does get harder, but it is a game mainly based on trial and error rather than skill. That means that the difficulty level only really goes from very easy to easy.
The real reason you'll enjoy playing this game is because the graphics are amusing and addictive, watching one bird knock an entire piggy fort down will keep you playing for a good 8-10 hours. Which makes it perfect to play whilst commuting.
Final word: 59p.. Not many games offer such good value for money.