These are all features that I've developed initial code for, player-side. They still all need to be bug-tested more, and may have room for improvements in exactly how they work. How much work remains needed in the editor varies, though all of these (where relevant) have at least a little bit of editor-side code written.
Limited-count entrances and exits - Pretty self-explanatory. This lets you have entrances and exits that only release / permit up to a certain number of lemmings. Fallback code is in place to ensure you don't end up with a level that has a higher lemming count than can be released from the entrances, or a higher save requirement than the exits allow for (it'll reduce the lemming count / save requirement to the highest possible value for the level). Editor-side, code exists to preserve lemming count caps, but not to edit them. It's possible for custom entrances / exits to have custom digits and a "close" animation (pending the acceptance of the new animation system, but that's looking fairly likely now); but the feature is also 100% compatible with existing entrances and exits (regular or locked), simply using the countdown digits as a default and indicating used-up purely by the count being zero.
Neutral lemmings - Neutral lemmings cannot be assigned skills, but in all other ways act like regular lemmings, including that you can rescue them and they count towards the save requirement. Neutral lemmings can either be pre-placed, or spawn from a neutral-lemming-spawning window (which, just like a zombie or permanent-skill window, is just a regular window that's got a "neutral lemmings" flag activated). Full editor-side support for this has been implemented, except for drawing preplaced lemmings in a neutral lemming color (and the editor doesn't do that for any existing color variation, eg. athletes or zombies, either).
Piece grouping - Allows creating composite terrain pieces out of smaller pieces, in custom levels. Those who are familiar with Lix will already know how this works - NeoLemmix's implementation is very similar. Editor has support for creating and using piece groups, but doesn't yet have support for loading and saving them - though I believe adding that support is quite high on Nepster's todo list.
Username & replay matching - Allows entering a username, which will be saved to your replay files. Replays with a different username (or no username) will not modify your level completion statuses or your save / time records. There's no editor-side support needed for this feature.
Please note:
- Shimmier isn't on the poll, because it's more or less confirmed for the next stable version anyway, so no need. (EDIT: To clarify, I mean the next major stable version. IE: 12.5.0 or 13.0.0, as applicable. If we release a V12.4.1 update, it won't contain the Shimmier yet.)
- Expanded skill limit isn't on the poll, because no coding work has been done on this yet. If I code it to a near-complete state in the near future, I'll add it in. It's possible to change your vote on this poll, so don't withhold votes for now "in case expanded skill limit gets added" - you can change your vote later if it does get added before the poll closes.
- This topic is not for discussing in depth how any of these features should work (if you'd like to clarify how they already work that's fine, as it's relevant to this topic; but if you want to discuss changes, let's use a separate one), or proposing other features you'd like to see in the near-future. Use the Bugs / Suggestions board (creating a new topic if none already exists) for that.
- We're under no obligation to implement features in the order this poll determines; it's just for us to get an idea of which features are more desired. We might follow it exactly, we might not.