Its comprehensive... but there are some instances of passive aggressive wording which have no place in a guide. These first two paragraphs I feel set a bad tone for the rest of the guide but if they are changed, it's all good.
"Mewtwo is a glass cannon. Before people go rambling on about how low his placings on the tier list are think about this. The Metagame of Mewtwo is barely scratched, his AT's aren't explored, and he has some amazing upsides with downsides that pale in comparison. Mewtwo is a character that will only be as good as you make him to be. To me, he is easily top 30, he loses to top tiers, but beats most mid and low tiers rather easily. Mewtwo's MU's rely on how easy it is to punish the opponent. So just think about this before dismissing him as a bottom 5, he has a great recovery, punish game and MU's against mid tiers. If your looking for a bad character then move along, because Mewtwo is anything but a bad character. He is undeniably a solid mid tier pick.
Mewtwo is one of the more difficult characters to play in sm4sh. The reasons for this are probably his annoying downsides, and his unorthodox play style and combo game. When he first came out, everyone dismissed him because he didn't have a combo game and his weaknesses were seemingly insurmountable. However, Mewtwo is not nearly as bad as he first seemed. He has amazing combos, great kill potential, fantastic recovery and stellar defense. When used correctly, he is a pleasure to watch. When used incorrectly, it is painful. Mewtwo requires so much time and training, and the reward is slight. Mewtwo is a character you have to want to play."
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Since its your guide you are perfectly allowed to be subjective throughout it, but I think if it was more like this it would be better for new people to read.
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"Mewtwo falls into the archetype of a Glass Cannon. He is does a lot of damage and KOs early however he is easy to KO himself. Unlike the typical glass cannons who are small, fast and rely on relentless aggression, Mewtwo can switch between a high risk high reward playstyle to go for extended combos and chase opponents offstage or set up a defensive wall thanks to his large range on many attacks. Mewtwo has a diverse matchup spread which while like most characters, struggles versus the top tier characters, Mewtwo can hold his own and beat the majority of the cast when the correct playstyle is chosen for the right situation.
Mewtwo in Smash 4 has a moderately developed metagame but it has fallen behind many characters due to initial perceptions of his viability being poor. In a game where many characters have very easy and high rewarding grab combo games, Mewtwo lacks any true combos from this throws. As a result, he is unpopular and many people are unaware of how viable he is in the game. What Mewtwo lacks in throw combos he more than makes up for with a stellar punishing game, high damaging tilt combos and the 2nd strongest set of throws in the game. Getting the most out of these attributes requires dedication and practice, Mewtwo is not a character for those who want results quickly.
Mewtwos weaknesses however unlike his strengths, are very easily defined. His low weight of only 72 ranks him as the second lightest fighter in the game and is especially weak to off-the-side KO moves. His large frame may give him long range but it also gives him a large hurtbox which can be easily clipped during his ledgesnap and techroll. Mewtwos out-of-shield options are powerful but not quick enough to escape shield pressure that top tier characters can put on him with his fastest actually being his upsmash, a risky move to throw out in defense.
If you want to main Mewtwo you need patience and a lot of it. His combo game is unorthodox but extremely powerful, his recovery goes an extreme distance but needs precision on the teleport and his playstyle requires a rapid shift from defense to offense at the right time. Mewtwo has without a doubt, the widest array of the strongest punishes in the game. Choosing the right option at the right time is critical as failure to do so leaves Mewtwo vulnerable and a character of his weight can not afford to leave himself open to punishing. Study this guide and you will learn all that you need to know to make the enemy scared to approach Mewtwo, not knowing what elaborate combo he is about to pull off to end their stock at 40%.