I have an Iphone 3G with OS4 and Castlecraft crashes so often that is unplayable but I can play it on my wifes iphone 3g that is currently still on OS 3. Crashs often but if you are patient and like the game, is playable.
I know is late for most people, hope thsi help someone. (in generalr OS 4 sux for 3G)
It looks like you're new here. If you want to get involved, click one of these buttons!