Yeah I don't have an excuse for my tardiness. Now this is an interesting episode. On the one hand I've been wanting Metal Sonic in an episode ever since Eggman VS Wily (exactly 50 episodes ago!) but on the other hand while I do enjoy this episode, its not without its flaws.
Analysis
Metal Sonic's rundown starts with the standard background analysis and does a god job covering his arsenal while also giving a nice Terminator reference. They go through his feats rather well although its here where I start to have a couple nitpicks. I really don't think using the Olympics spinoff games should count as it can apply to pretty much everyone in the Sonicverse. Also I have a problem regarding Mach 8 Sonic because he does actually have one feat that shows him moving at FTL speeds. In Sonic Generations he was able run fast enough to restore the space-time continuum and while I understand its a MASSIVE outlier, Mach 8 is just a bit too slow in my opinion. An additional nitpick to this is that it wasn't even necessary considering that Metal Sonic himself moves at Mach 35. However, I do think that it was an interesting piece of information and while I disagree with it, it was nice to see them convert SPD into meters per second (as well as debunk that horrid game theory) and it gives Boomstick an opportunity to make another jab at his ex-wife. The stalagmite feat was also a very interesting piece of information. The rest of Metal Sonic's analysis was pretty good covering Metal Sonic's alternate forms and weaknesses.
As for Zero's analysis, it gives a much more detailed rundown on his background, probably due to the fact that Zero is an actually fleshed out character. It does a decent job at going through his arsenal and alternate forms while throwing a joke or two in there to keep it entertaining. It covers his feats fairly well though I do have an issue or two which I will cover in the conclusion. However, this rundown does use the calc omission trap by giving the statistics of Metal Sonic's feats but not Zero's and as such I did know he was going to win. I give this analysis a 6.8 out of 10.
Animation
You know I once claimed that Jetz was the Torrian of 2D battles and I think this episode proves my claim. The episode shows that Jetz has just continued to improve and the 2.5D actually works well with the fight. Sure there are some shots that look a little off but that just means it'll be easier for his next animation to beat this one.
Although the animation could've made better use of Metal Sonic's Scan and Copy ability as he uses a charge shot prior to copying Zero's charge shot so it makes it a little difficult to understand that he actually copied anything. Furthermore wouldn't the Z-Saber count as Zero's signature ability?
However, that's about it for nitpicks. From here on out, the fight just escalates with each combatant countering each other like a strategic game of chess. And then Metal Sonic turns into Metal Overlord and the fight becomes a David VS Goliath fight like we haven't seen before. We are then treated to both combatants shaking off each others attacks until the climactic finish where Zero slices through Metal Overlord in one strike. That would be a moment worthy of 'Rules of Nature' right there, of course Zero doesn't look back as Metal Overlord explodes. I give this animation an 8.8/10.
Conclusion
Now before I start, there is not a doubt in my mind that Zero would've stomped Metal Sonic. However, much like Sub-Zero VS Glacius, the reasoning is what is important here. For speed, they don't actually give Zero any feats or evidence that he would keep up with Mach 35. Instead they use speed scaling which I am not a fan of. Speed scaling relies on the assumption that said character scaled was moving at those seeds during the fight. Furthermore they make it complex by scaling Zero to Mega Man who in turn is being scaled to Quick Man. The episode's entire argument for why Zero is faster (or has better reflexes, whatever) is based on an assumption based on an assumption. They also use the assumption that Zero is better than Mega Man based on the fact that he was built to surpass him yet has never shown this in a direct fight. Yes I do know that Zero is better than Mega Man but that was because he was introduced in the X era where the series started to get more and more absurd with his feats. Also Metal Sonic was built to surpass Sonic but has consistently shown to lose to him. Even still Metal Overlord has reacted to Super Sonic who by Death Battle's own admission has gone at FTL.
Now they do make a good point about Zero's superior and much larger arsenal which allowed him to counter anything Zero could throw at him. I also agree with them on the hax side of things where Zero's means of stopping time were generally more effective than Metal Sonic's.
As for durability, yeah no. There are multiple things wrong with this feat such as the fact that the space shuttle tanked most of the damage. Of course Zero wouldn't have gotten out unscathed but there is too little evidence to suggest he tanked even a fraction of the supposedly 100,000,000,000 tons of TnT that they are saying he did. As shown by this episode's own footage, the shuttle is relatively unscathed and as such assuming Zero tanked this is unreliable at best. From the sounds of things this feat was merely a character statement (which tend to be quite slippery) that said it was similar to the meteor that wiped out the dinosaurs and does not explicitly state that it was 100,000,000,000 tons.
Like I said, I truly do believe that Zero wins this matchup. Hell its not even close but the reasoning used to justify his win in this episode is too circumstantial to be used reliably. I give this conclusion a 5.4 out 10 for a total score of 21/30 or 70%.