Draft Regex Golf Bonus Levels

 1.0) Subtraction: http://regex.alf.nu/?set=096c2851405041e914554d6569c7b12b282e5b8c
 2.0) Anyway: http://regex.alf.nu/?set=e8bae464b482dfe68f03083276d8759ee4d0000c
 2.1) Anyway: http://regex.alf.nu/?set=12fda3525a9f0964e82f19c9b30333f15abf57ab
 3.0) Addition: http://regex.alf.nu/?set=a3598dad86891467275fe5b784902b093e01cc5b
 4.0) Coprime: http://regex.alf.nu/?set=04963affd55e2a487195995c9a9c8a3060ab0623
 5.0) Typist: http://regex.alf.nu/?set=814323f64b3028f3774526362d6516aba5c732e2
 6.0) Dominoes: http://regex.alf.nu/?set=d706fb7a1a939704a009d6d3da9e53217a733187
 6.1) Dominoes: http://regex.alf.nu/?set=9e055be1a701c710ca9ed731af041fa2d6a9d478
 7.0) Modulus: http://regex.alf.nu/?set=1d0701393c93cb937872f119ccfd5f4e13771c73
 8.0) Euclid: http://regex.alf.nu/?set=40da988035bc832a637fa95f1dd579c93396df69
 9.0) Latin squares: http://regex.alf.nu/?set=02c95a9dec7cc53c70c364ad5b56eb6e316f2821
 9.1) Latin squares: http://regex.alf.nu/?set=742eab557c42499e5222b6a4642fe6a46380669e
 9.2) Latin squares: http://regex.alf.nu/?set=d88f72524efafbbfe80c36dc449e3c176f72b544
 9.3) Latin squares: http://regex.alf.nu/?set=1981d2ca1b570c5b737e27517358eed59bca53a0
10.0) Matryoshka: http://regex.alf.nu/?set=f2c77b400ad20bc3b522205eb0cdd5b5f9184eb7
10.1) Matryoshka: http://regex.alf.nu/?set=08ae234d43f95d09112b460ee06f042c569eb79a
11.0) Dominoes 2: http://regex.alf.nu/?set=b1ffdd1dd77a92053acd5792bcec7271e8c599d5
11.1) Dominoes 2: http://regex.alf.nu/?set=4da7bda7ef6c5d5cb9ba79cdd25ec3ae5fd7c280
11.2) Dominoes 2: http://regex.alf.nu/?set=0c4a5a9e2e4e9695edfcf5b3f7f08e6dfe1ba81e
12.0) Xor: http://regex.alf.nu/?set=ec60e1f78681fba20f74384e2d378e81ebb42ec0
13.0) Tic-tac-toe: http://regex.alf.nu/?set=57a44278bbf89cd219f465cde985fe8f2f7f3294

I don't think Typist is a very good problem. Perhaps it can be salvaged with a better selection of words.

I like Typist. It's a nice easy-level problem. Maybe you should move it upward, next to the easier ones, but the trick involved in shortening it is pretty neat.

Maybe instead of adding both "banana" and "eleven" to the left side of Anyway, you could add only one of those?

Thanks for the feedback. I won't start shuffling the puzzles just now but will indicate perceived difficulty. Once we have enough good problems we can decide on the order.

For Anyway, I've added "eleven" to the left and "mysterious" to the right. I've taken "human" and "plastic" out so that there are still 20 strings on each side.

I've tweaked one of the example strings in Latin squares so that it guards against a particular non-robust solution.

I think that's enough puzzles for now. I'll spend what time I can spare for this on sharpening up the existing problems and solutions. Following this, I'll reassess the difficulties and re-order the problems.

The Dominoes 2 strings have been completely reworked to make the subtleties of the problem clearer and to increase the number of false positives for natural solutions to Dominoes.

Dominoes 2 strings were tweaked to include some very short chains (lengths 1 and 2). These cases trip up a number of natural solutions.

Dominoes 2 strings were redone in light of work done by Davidebyzero.

Would you mind me using your levels on my site? I already have Erling's levels (with his permission) and it would be cool if I could add yours as well. Of course I'd mention you as the author.

Not at all. Please use them as you wish.