complete pack

If its like a private giveaway ask the creator they have to allow you

There is no explicit rule on SG for this case.

General answer: there is no SG rule that forbids you to enter.
But: common sense should apply.

Best practice for bundles: The giveaway creator puts a note in the description, where he states whether it's okay to enter if you have one game / most games / the base games / only 1 DLC / less than X DLC

As Drafke wrote: as the giveaway creator if it's okay to enter.

If you won the Alan Wake Franchise, for example, you won't get extra copies to give to others who don't have it, so personally, I wouldn't enter if it was just the DLC that I wanted. It'd feel like I wasted two games with quite a high value.

You could, but that is extremely frowned upon by most people. The giver also has the right to re-roll you win should he not be pleased with this result. The winner owning most of the pack is actually a valid reason for re-roll, and can be selected in the dropdown list by the giver.

okay thx /thread