Turtle. Project blue will be able to make you do virtually anything with your game. $28 seems like a lot, but if you read through the seemingly endless list of inmprovements, you'll see how worth it it really is.
Design, honestly, you don't need to use all of it's features. Think about it - buy project blue for a select few features - make a good game - sell it for a couple of £/$ to a few friends - make the cost of it all back. I didn't buy FPSC because it had a drag and drop level building system - plenty of game creators do that - I bought it because it has a rather simple program language, and has a few features I wanted, that other creators don't.
When I say a few, I mean a hell of a lot...