This should be red.
This should be huge.
This should not be red (only applies to block elements - a SPAN element).
This should be underlined and blue.
This should have a lot of extra line-height.
This should not be red (pseudo not subject of selector).
This should not be floated. That would be wrong and would make the browser buggy (although that's hardly anything new. Is it now?)
Blue background.
The blue background should only be behind the text, since :first-line selects the content in the first line rather than the first line itself.
This should have a lot of letter spacing.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should have a lot of word spacing.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should look normal.
This should be vertically aligned differently - raised by 3 cm.
This should not have more margin. Otherwise the browser would be buggy, which isn't good (but hardly surprising).
The picture is here: 
This should be flowing around the image, despite what the CSS spec states to the contrary - :first-line selects inline content, and clear has no effect on inline content.