I have to say, this was interesting plot wise. To be honest, the plots of initial episodes were very difficult to put into any meaningful context. You had a basic idea of what was going on, but didn't really have enough information about the world or anything else to make meaningful determination of what anything meant long term. In other words, we couldn't see much pass the individual missions. The only exception for that was the arms dealer they caught who seems to hold important information relating to something big. Not that this was a bad thing. That is the style you are going for and the nature of this kind of series. But now we have just a bit of direction. We finally get to understand a bit more about things such as the hierarchy of the organization, potential motives, and the situation of the wasteland people referenced briefly in the first episode. It is starting to tie together and this is a good thing.
Speaking of plot, how about that blue Tobi mask? I was not impressed by it, but I did find it interesting that the "purge west town" douche bag has a red eye thingy in the exact same spot the masked thing had. Regardless, I get the sense that he is clearly not the friend of the protagonists.
The blatant Naruto models were somewhat disappointing. You have done it before and I do 100% understand the reasons why you do it. But when it becomes too obvious, it takes away from the video. If it was better hidden then I wouldn't have a problem with it. But you do have to hide it. And then there are the inevitable changes and improvements that come, but even more so if you start with a copied character model. While I greatly encourage trying to improve things such as character models, I also find the sharp changes in character that sometimes occur between episodes to be a bit hard to stomach. A bit more subtlety over time would be easier on me as the viewer to keep up with. That can be hard to do when you start with copies from well known shows and work from there. It almost requires drastic change from the start.
But to be fair, this has not been much of a problem in this series so much as it has been in other series. In fact, I would say continuity despite improvements has been an overall strength of Arc Infinitum so far. I just get worried to what things like this might lead to, as well as what it takes away from the experience when I see things which I cannot possibly look past like Tobi's mask.
Anyway, I thought the episode was overall pretty solid. It just wasn't spectacular. Like it was missing the life almost. To be clear, you have improved a lot from the first episode. The beginning sequence was really nice. This had good plot development and the action sequences were for the most part set up pretty decent. I really liked the use of the duds (is that what they are called?) in this one. It looked much more believable, which is (again) different from realistic. The Tobi's mask fight looked a bit odd, but only a bit. I'm not going to nitpick like I have in the past because A. there's much less to nitpick and B. everything I could bring up has only improved over time.
But at the same time, this episode was lacking that feeling. I don't see the edge I saw in the first couple episodes. While the voice acting is good, it feels like there isn't a lot of life to it. The episode is well put together and organized, and yet it just doesn't quite flow. I can't even put my finger on it exactly. There just needs to be a better job at selling the drama and the tension in general so that I as the viewer don't stay emotionally detached for 9 plus minutes. As interested as I was in the plot. Correct me if I'm mistaken, but I think I read you saying that the next episode is a plot driven one. If that is true, then this aspect becomes even more important.
All in all, though, I am encouraged by the episode because you are steadily improving at pretty much everything and it does not go unnoticed here. Many of the individual aspects are better. It's just that tying everything together (even if it was individually mostly better) was a little weaker in this episode. Something that is very important to me as a viewer is the feel of an episode or series. Generally, I find this to be an overall strength of yours so I don't think it's really a long term issue. It is kind of an abstract concept, but your first two episodes had it despite having larger flaws at spots than what I could find in this episode. It's not that the feel is bad here. It's just not as good a feel as the first two episodes, and I think that is what takes away most from it despite many things being better here.
So I gave you an 8/10 or a 4/5. Pretty solid video with many individual improvements. Just bring back a little edge and fluidity to it and I see no reason why the next one can't be damn good.