Putting together the feedback from the last two pages:
The "Extra" rank are levels that had less support to begin with than the main levels, so they shouldn't be re-added without strong consensus. Only two Extra levels have had multiple votes in favour: "Worra load of old blocks" and "With a twist of lemming, please". The only level outside the current pack whose reinclusion has been suggested is "The Steel Mines of Kessel".
So, we should consider these three levels plus the main 150 as our pool, and decide on exactly three levels to leave out (which may, of course, include some of the above suggested additions). "Last Lemming to Lemmingcentral" should certainly be dropped, as it's trivialised in NL due to the ability to explode lems in the first five seconds out the hatch (this was simply overlooked earlier). It looks like there's a fairly strong consensus that "Lemmintaschen" is weak and shouldn't make the cut.
For the final level to drop, I certainly don't agree with cutting "Sega Four"; not only is it a good level, but we decided to keep it as a sort of equivalent to a special graphics level so as to keep one in each rank. "It's the price you have to pay" is really the only one that stands out as having several votes against, though another possibility is "All the 6's".
So, having got this far, how do we make the final decision? Should we have a last vote on the borderline levels, or just go with these additions and removals and call it a day?
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I'm strongly opposed to cutting Fun 1-7, because I think it's the perfect way to start a level pack, with simple levels playing with the skills one at a time so the player will definitely get used to all of them. Just look at how many usermade packs start in this fashion, even when the pack as a whole is clearly aimed at players already familiar with the game.