I discovered the problem with Hex Map on the iPod touch last night: the app uses way too much memory for all but the most current of iDevices. The iPad, iPhone 4, iPhone 4S have 512 meg of RAM; earlier models and all iPod touches have 256M or less. Almost any use of the app on one of those 256M devices causes it to run out of memory and quit. I’ve tried scaling back the functionality to cut back the memory footprint, but it’s not easy. Basically, unless I got back and re-write the app (using tricks I don’t yet know), it’s not feasible to run it well on iPod touches.
I hope to test a semi-crippled version of the app on a few more devices tonight and start the week-long process of getting the new version into the App Store. At least it’s a free app so people can’t complain too much.