Thinking about the recent discussion of nuking and neutrals, I realised there is a problem to be solved concerning the user interface.
At the moment, three values are displayed: (1) lemmings still in hatch; (2) total lemmings alive, including hatch; (3) lemmings saved minus the save requirement.
(3) is unproblematic; and if neutral hatches exist, the purpose of displaying (1) is so the player knows when the last lemming comes out, so clearly the right call is to make this value include neutrals.
The difficulty comes with (2). If it doesn't include neutrals, then you can't compare (2) and (3) to know whether you are in an unwinnable state. If it does include neutrals, then there's nothing in the UI specifying the number of active lemmings available, and in particular, nothing that points out when you have no more active lemmings.
Maybe (2) should be replaced by two separate indicators, for the number of active lemmings remaining and the number of neutrals remaining (including hatch in both)?