Is there any differences between game releases for different regions (ntsc-u/c, ntsc/-j, pal-uk and pal-aus)? I often hear that ntsc-j games releases get changes to gameplay/names etc. when localised for western regions. I also hear sometimes of american/british english script differences between ntsc-u/c and pal-uk game releases. Are these correct?

I am aware of regional differences like box covers being different and technical aspects (pal-50hz, pal-60hz and ntsc-60hz).

Also, are there any differences between games with a budget range realease (platinum, greatist-hits etc.), special package release (limited edition etc.) or online release (PSN etc.) compared to just the original, physical release?