It's not bad. I mean at times it can be addicting, but there are a few problems with this game.
I think one of the major problems is the control. It's slips and slides everywhere. It's not too bad, but it's something that does get annoying.
The whole concept of the game is alright. I mean shooting birds with a slingshot? I really havn't heard of a game that does that. Untill now of course. So I think this is really good in originality.
I would really like to see a Slingsot Master 2. There is much you could add to this game. Like new targets, ammunition, possibly slingshots. There are endless possibilities. And the fact that you can add upgrades would be a nice touch to.
You have done a great job with this game. I will be looking forward to Slingshot Master 2 if you ever decide on actually improving it.