Hi, thanks for messaging me. Making this matchup chart is a great thing to do, and I'll definitely be happy to assist you with g&w matchups. I checked it out, here are my thoughts:
I totally agree with the sheik matchup, the matchup is extremely difficult for g&w, he gets cg'd, gimped from needles, etc. Brutal matchup there.
I would like to think that the g&w vs marth matchup is only a "disadvantage" for G&W. I cannot really verify this, because I do not have as much experience against marth, as I do with some other characters, but here are some reasons why I feel it's only a disadvantage:
1. G&W lacks the range that marth has, but he has priority which is equal to or greater than most of marth's moves. For example, a simple dash attack from g&w will "clank" with a marth f-smash. After this clank occurs, g&w can jab, followed by either a d-tilt or grab, and begin combo'ing.
2. D-throw combos. Once G&W gets a grab, the d-throw combos are nearly endless. At low %s, he can d-throw to f-air/judgement, and at high %s d-throw to n-air is guaranteed to get marth off the stage. Additonally, on stages with platforms, the d-throw OR d-tilt will get marth on platforms, which g&w can brutally take advantage, since G&W has priority over marth when marth is above him. A marth on a platform can be d-air-> n-aired for a kill, regrabbed, etc.
3. G&W can gimp marth. Of course marth can also gimp G&W with his tipped f-smash, which can be devastating on small stages like YS. But G&W can also do the same to marth, it just requires more timing. When G&W hits marth off stage, marth is very vulnerable. Here are some reasons why: When marth is forward b-ing for horizontal recovery, he is vulnerable to G&W's n-airs and f-airs, which would be a stock. But you could say, a good marth won't allow you to get him that easily, because he would lower himself to sweetspot range. In that case, if g&w throws sausages to edge-guard marth, the sausages drop down belows the edge, since they are like no other projectile. And when ANY character gets hit by a sausage or 2, it makes it quite difficult to re-sweetspot the edge after up-b'ing. Thus, G&W can take advantage of this and gimp with a d-tilt or a fastfalled n-air.
...Just my thoughts on marth
FALCO
in my 4 or so years of maining G&W, this matchup is the matchup I've played most. I think I am the most knowledgable at this matchup. I've taken games off of some good falco players such as zhu, D1, doyoung2win. And i honestly believe that this matchup is only a SLIGHT disadvantage for g&w. I'm actually in the midst of making a pretty extensive matchup-discussion about this matchup which will be posted on the official matchup discussion for g&w on the g&w boards if you wanna check it out, but here are the general reasons why i think this:
1. Falco and G&W both combo the s*** out of each other. Falco's combos are pretty automatic, whereas G&W requires some tech-chasing and prediction.
2. Falco's lasers do not ruin G&W's life. Yes it is difficult to approach falco or be approached by falco when good laser-spacing is involved, however, G&W has the priority to be able to attack falco from above. Especially on stages with platforms. I will admit, fighting a good falco player who knows how to properly space his lasers on stages like FD and PS is pretty difficult. However even on those stages, G&W has brutal CG combos that can result in gimps. But on stages with platforms, G&W performs even better, with the exception of battlefield, since the placement of the platforms on that stage really help in falco's favor. On stages with platforms, G&W can use the platforms to his advantage and as an escape from lasers, whereas most characters (if not all) cannot. Once G&W is on a platform, you may think he is in danger of getting aerial'd, but with attacks like his d-tilt and and d-air, which have great range and some of the most priority in the game, it gives falco a hard time to hit G&W from below. If Falco instead full hop lasers or lasers from another platform, G&W can now waveland on to the bottom platfrom and now be below falco, where G&W also has the advantage since his u-tilt, u-air and n-air ALL have priority over ALL of falco's aerials. Additionally, if falco gets hit from g&w d-tilt or d-air, G&W immediately starts combo'ing with a some tech-chasing.
3. Falco is pretty easy to edge-guard and gimp. One grab at the edge of a stage and falco is most likely going to get gimped. The reason why this is true is because it is difficult for players to realize which direction they are getting thrown in to DI it properly, since all lf G&W's throws look quite similar. So if I were to throw a falco away from the stage, and he DI's towards the stage, I get a free f-air hit, stock. If i do the same throw and this time falco DI's away from the stage, now he has to recover. G&W has edgeguard moves that are very fast and unpunishable. For example, lets say i predict the falco is going to forward-b illusion to the edge. because of this, i use d-tilt. However I predicted incorrectly and he instead uses up-b. Because the d-tilt has such a short duration of post-lag, I can now get ready to edgeguard the up-b with either another d-tilt (if i predict he's up-b'ing straight ahead, upwards, or from below), an f-air or n-air otherwise, and falco will lose a stock.
I can talk about it this matchup more if you want, but I really do think that that is the matchup
Also I think that since I'm not a very great player, and I'm able to beat very, very good falco players, that THAT has something to say about this matchup. Just sayin
I'll get back to you about more matchups later, take these into consideration! Hope it helps.