I noticed that Opera browser is in version 12.16 for Linux version 22 for Windows.
Why is there such a dramatic difference in version numbers?
Opera 22 is not the Opera you know and love. It is a completely different program, contains no old Opera code and is based on the Google Chrome codebase.
The original Presto-based Opera has been discontinued after version 12. It is still supported for security fixes, but no new features will be added and websites may get borked.
Starting with Opera 24 you'll get a Linux Build again. But as @kinokijuf said, this new version is completely based on Chromium Code and has nothing to do with the old Opera.