Thought I try something. I am going to exclude certain elements because they are previously existent in Portal 1 and I may create a poll for that as well.

I notice test chamber designers tend to have a predisposition for using certain elements in their puzzles. What is/are your favorite testing element(s) new to Portal 2? I like gels but specifically propulsion gel the best. All that running around jumping long gaps. Combines well with momentum conservation with portals. Also combines well with propulsion gel to cross even larger gaps and momentum bounces.

Am I meant to vote for one or a few?

I allowed up to 10, which is the max amount of items a poll can have.

I'm disappointed that the light bridge is lagging behind! How could anyone not think it's the best?