Oh this is awesome! For those who don’t know, I helped make the HD method and NLL stands for Neuro Last Layer. It seems it’s more competitive than we creators thought. However, there is a major issue inherent to the method:
Difficulty 1-looking.
Reducing the cube to a state required for NLL involves two major steps: Guimond Layer and CO+V. Now, a Guimond layer is very easy to do, but one must also know what CO case they’ll get and how to make a V once it’s been executed. Then they have to predict NLL.
This is, in my experience, much more difficult than 1-looking with CLL+EG1+EG2. That alone makes this method unviable in my opinion, as I think a good 2x2 method should be one-look-able and have good movecounts/algs. HD-G only has the latter trait.
Still, I could just be an idiot with poor look ahead, and there is value in novelty methods. I’d love to see HD/HD-G brought to its full potential.
This is actually so interesting because I feel exactly the opposite. For me, HD-G ( I can't really speak to HD because I am less familiar ) seems like its far easier to 1-look. Firstly is because you can pre-memorize how the Guimond CO alg will effect permutation. Given the fact that the average distance to a Guimond 3/4 face is 0.16 this becomes very easy. The second reason is due to the fact that HD-G orients first. This means when you're tracking the rest of the pieces for the rest of the solution you only have to worry about permutation, not both permutation and orientation as in EG. Lastly, as mentioned before, very very often you're only required to modify the Guimond alg by doing a R instead of a R' ( and vise versa ) to solve the V. The other nice solution is that if the R/R' doesn't form the V you can just work through several solutions which will produce that V.
Example:
Scramble: F' R' F' R2 U R' U' F2 U
So here we can look to 3 solutions:
(1) z2 // Here we have the Red/Orange V and immediately l see that the stickers are arranged in a opposite pattern ( no 2 stickers are set adjacent to one another). This is a bad situation because we produce 2 bad situations (a) where a Red sticker will be placed in DFR meaning we will have to add an additional move to create the V and (b) where an Orange sticker will be placed there which would set the V an D2 away.. not great. So I'd just avoid this.
(2) x2 z // Here the you have 2 adjacent blue sticker which is much better but still not great. The best Guimond face is going to be 2 matching stickers on L ot R. Luckily the way to solve this case is y' U2 R2 U R' U2 R' which places the bar on L. Here ( after the y' ) UFL > DRF > DBR. Since the alg is 2 gen the DFL and DBL are untouched. Good but I got one better.
(3) x' L' // Here we are 1 move off from a Guimond face that produces a 3 move case which is the easiest to track. Here I'd actually do y2 U2 R' U R instead of U2 L' U L as it sets up the V correctly. the alg doesn't effect the rest of the V and we only have to track 3 remaining pieces in the U layer.
8/15 Guimond algs are 3 moves. Another is 4 moves but is sneakily just F into a previous case. Since all but 1 alg is 2 gen the DFL DBL pieces always stay the same.
This is probably longer than it needs to be but here you go.
tldr; Tracking orientation and permutation is harder than just tracking permutation. Easier to track pieces through an alg as it always has the same effect and you don't need to do it on the fly.
Also an honor to have your input!! Very fond of this method

Hope we can see it grow!! I think it has good potential and it seem some other people do as well. Would be awesome to get some reactions/input of top level 2x2 solvers.