Hehe, nice discussion! I lean more towards @Zhenmuron's opinion that the genre has been around for a while now; I can't speak for Tristan and James, but I think I drew most inspiration from SFCave, myself. That's not to say we don't like Tiny Wings, but I think we've each played it only about three times apiece. So if we'd been trying to clone it, we'd have been going about it the wrong way! ;^)
We have been quite unapologetic in trying to create something that will be popular, though, basically to help us get to make Scarlett Episode 2. :^D I wrote a couple of blog posts back in March on the issue (and also on how we picked what became Mighty Fin from amongst our prototypes):
A change of schedule
The Face-Off
@Ricardo1980 and @ddeaco: We needed to store our alpha-less spritesheets as JPEGs in order to fit under 20Mb, but JPEGs are very slow to decompress (especially on iOS 4.0, what with issue 886 and the further conversion to png). I hacked up a class which dumps the generated texture bytes into a disk cache, and when the JPEG is asked for a second time, the raw bytes are loaded instead. The unpacking screen just requests all the JPEGs in the game, then discards the ones it doesn't need immediately.