You can do an "apt-get upgrade", it just breaks one hildon layout package which you can fix by deleting .osso/hildon-desktop folder in your home dir. I did it on my 770.

About applications: e.g. I tried pokerth today which is a qt poker client/server. It installed and ran ok, but you need bigger screen and can't make text input. So I installed synergy, and using another computer's keyboard and mouse on the IT (this way you can put text into Midori, etc). There're a lot of packages in the repos, you can give them a shot. Maybe a thread for not working/problematic apps would be a good idea.