I've finally finished the game this weekend. There are indeed 4 ratings of 15 levels each.
I have attached (rather than directly link to the images, to avoid spoiling it) the ending. Unlike the opening, there are a small amount of animation in the ending, but the screenshots is more than sufficient to show what the ending looks like. The text scrolls throughout the sequence. Nothing happens after the final screen (it doesn't go anywhere after that and you'd have to reset).
Overall it was a functional clone of Lemmings, and if you compare against the official Lemmings ports on Nintendo and GameBoy, Ant-Soldier is not too bad aside from fewer levels and cruder animations (and maybe slower skill execution) in game. The level difficulty is interesting--whereas levels in earlier ratings seem less forgiving compared to the original levels (in terms of skills given and save requirement), in the later ratings the difficulty isn't especially harder than the earlier ratings. The second-to-last level in particular is unexpectedly a fairly straightforward 20-of-each level (almost no other level even give you 10 of one type of skill besides builders) and can be completed using just a couple (under 5 of each IIRC) of builders, diggers and bashers.
Some levels from the original Lemmings game do make an appearance in this game, whether in terms of the conceptual solution or in terms of the level's visual design (or both). Examples I noted include a few of the "skill tutorial levels", Compression Method I, Let's Block and Blow/Bomboozal, Pea Soup, Lemmingology, The Fast Food Kitchen, The Far Side (though with a major non-glitch backroute), and probably a few more I missed here. There are a few repeats but nowhere as many as in the official game. Ultimately though there aren't many levels with standout, particularly memorable solutions IMO. The level (3-7) that is based on "Compression Method I" is pretty much the height of "memorable, interesting solution" for the game, to give you an idea.
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Aside from confirmation of its existence, there doesn't appear to be a huge amount of written information about it out there.
Well, now that I've finished the game, I can certainly provide any amount of written information about it as you like. Just ask here!
I'll probably upload the list of level passwords to GameFAQs or similar. I will attach the list here later today.
