This was decently enjoyable. It might not have the professional voice acting of an actual anime, but the fact that this was a collaboration of different fans makes it enjoyable to watch.
Although, there were a few parts in which I felt could have also used additional dialogue, such as panic, gasps, yelling, or even combative dialogue. Areas such as battle scenes and Reimu's intro into the Yuyuko battle.
For example, some scenes seem to rely too heavily on the music, and they could have utilized speech such as Youmu saying, "Why won't you die?!?" Or Marisa yelling, "Nearly bought it on that one!"
I felt that it was slightly strange that you skipped out on the entire section of stages 2-4 and the extra character, meaning Aya, Chen, Alice, Lily, and the Prismriver Sisters. While those parts don't have dialogue per se, you could have added your own interpretation of what occurred then. Examples being:
Marisa: Oh great, it's paparazzi reporter one.
Chen: Can't catch me~
Alice: Sigh Marisa, what are you doing here?
Lily: Yo, Spring is here!
Prismriver Sisters: Just their music
The fourth wall breaking was alright. It can lend itself to either being well humored or simply over top in the sense that it can be very funny, or it can come off as being too well, over the top in speech.
Youmu: OH SHI-
Also, shouldn't the second later that day have been earlier that day, since Reimu would have needed to make it there? And a suggestion that I have for avoiding the later that day black screens would be something that forces a transition. For the first, something like, "Well, Elsa's dead. Let's just ignore stages 2-4, nobody cares about those." The second being, "Wait, where's the Shrine Maiden?" "Being a lazy ass."
If there's anything that needs more clarification, don't hesitate to ask.
Canon was killed several times over then tossed into the grave, but it was still fun to watch the skewered version.
-Shadow1176