Restoring to Factory Settings and Restore Backup on an iPod Touch 4G

Question

I have seen many posts regarding restoring iPods to factory settings and then loading a backup.  I have seen many posts about the "Other" storage space, too.  But I haven't found any that address my specific issue.  I'm mostly looking for some assurance that I won't lose all of my son's and daughter's hard work and the money we've spent on a couple games.
I have reviewed the Usage on my son's iPod via Settings < General < Usage.  I added up the storage space of all the apps.  It is 2.1 GB.  This is what the "Apps" category shows is being used.  The "Other" category shows it's using 2.3 GB.  It is only an 8 GB iPod, so this "Other" is eating up a ton of space.  He has no videos, only pictures he's taken (which isn't very many), apps (I keep those at a minimum), and music (which I also keep tight control over).  How do I find out what this "Other" is, and how do I get rid of it?  He doesn't have e-mail, and doesn't use the calendar, contacts, or notes.  I've read posts which say I probably have corrupt files and have to perform a factory restore, which wipes everything out, then restore again from the latest backup, with no guarantee that the "Other" will go away.  I've also read horror stories about the factory restore causing problems with the basic function of an iPod.  I called Apple Support, and the young man I spoke to asked around (because he didn't know) and said that the data while using an app (games like My Horse and Angry Birds) is stored in the "Apps" category.  How can I be sure of this?  He has a game we've put a lot of time, energy, and some money into.  I do not want this to be lost.  I'm assuming that backing up from the lastest backup of the iPod will prevent this, but how can I be sure that the game information isn't part of the "Other"?  If it is part of the "Other", and it doesn't get reloaded to the iPod from the backup restore, then it's lost.  If this happens, I will be very upset.  I'm frustrated and confused by all the conflicting information I've read.  Does anyone know where the game data is stored?  Does anyone know if the "Other" will be restored from the backup, and thus make the entire restore process pointless? 
Please help!!

Answer 1

As you likely read already, the "other" category consists of those items not included in the enumerated categories. That is why it is called other. What is in it depends a lot upon what different app place it it.
2.1 GB seems large enough to it also contain corrupted files.
Usually restoring from backup reduces the other. However, sometimes restoring to factory settings/new iPod is necessary since the larger other may be included in the backup.