Very addicting and loads of fun - even for us "older" players BUT, and it is a very big but, why dont you do anything about the cheaters that take away the fun? Spending the time, and unfortunately money, to try and get the best possible score for the levels and then you see an impossibly high score pop up just when you were about to be number one, or even in the top five! Seriously, all targets destroyed, a really good score, then another score pops up thats thousands, and sometimes tens of thousands, higher; how is this possible? Well, its not - not without cheating it isnt anyway!!! As the creator of the game, you should be monitoring these cases and close those cheating chances. The game can be fun, and can get minds thinking (even uses physics and problem-solving skills to get the high scores) but when cheating seems to not only be allowed but encouraged, as evidenced by the rewards attained at the end, the game just turns into a reminder that, as in life, the cheaters always finish ahead; at least until they get caught! So, Rovio, police your game(s), and throw the cheaters out! Lets make the game "fun" again!
One other thought to maybe improve; why dont you add the cannon to the sling shot choices? The cannon has been used in several levels so it seems logical to add it as a choice now?
Out of many one. about Angry Birds Friends, v3.1.0