I can't find plastics.
Video mode has an extra ball on screen 2. I don't think it is available if you already have an extra ball waiting (not sure on this) I don't know what comes after screen 2, haven't ever cleared #2.
When you get Crazy Bob's items, it gives you a time advantage during power down, if I remember correctly.
NO idea on the combos
With the rest of the things I will have to check mine when I get home.