The game looks quite different from the original Mushihime games. (Reco seems to be walking and not flying, for example), The object here is to blow up bugs, and chaining is possible.
Cave plans to release more games on the iPhone for the European and American market. As Hobby Blog points out, Cave has decided to use the iPhone platform because shooters are such a niche market outside Japan, and it's difficult to find a distributor for console titles.
Mushihimesama Gaiden BUG PANIC iPhone [Hobby Blog]