If this channel feels like a blast from the past, that's because it is! Around eleven years ago, the host started this YouTube channel to teach Japanese. Although only a few dozen videos were released at the time, in the past year it's been revamped with tons of new content. Miho, who runs the channel, used to teach at the University of Pennsylvania, and knows English as well as her native Japanese. The channel is aimed at helping both English speakers learning Japanese, and Japanese speakers who are interested in learning English.
The length of each video depends on the content. For instance, the "3 Min Japanese" segments are some of the shortest and feature more conversation-like topics. The grammar videos are a bit longer, go into more depth, and provide examples. The longest are the shadowing exercises (which can be over an hour long) where everything is repeated twice. These are perhaps some of the most helpful videos for beginners, especially those who do well with repetition exercises.
The videos are targeted more toward beginner to intermediate learners, but she has content for all levels; the N5-N1 listening practice videos are a good example. The amount of Japanese and English used isn't always consistent, so you'll likely need some knowledge of both. One other thing that might be an adjustment to listeners is the higher pitched, slightly distorted vocal effect on Miho's audio, but you may not notice it to begin with. Unfortunately, video production stopped in August due to personal health issues, but we hope to see her back one day.