The length of this thing keeps confusing me. Every time I think that I must've reached the halfway point, it just keeps going deeper and deeper. For example, Mana's arrival threw me into a loop. It just made no sense whatsoever.

Since then I looked into the booklet, which says that Mana is going to be badly injured and hints that Kotaro has a chance to prevent it. Perhaps they want to force him to make a choice between saving Kaho and Mana. That would make at least some sense, but still...

Speaking of choices, I suspect that a vast majority of them are empty and the plot railroads the events. Indeed it's the only way to make the thing fit on DVD. For example, in the beginning Kotaro is offered a choice to discuss his predicament with Ai or Takeshi, whereas anyone with a brain larger than a pea would see that the only reasonable choice is to chat with Tomo. Which is what happens eventually.

Even when effecting an outcome, choices in Hourglass are often similar to elections: I have to select the least evil. It has a lot to do with the protagonist being dumb like a stump, which disappoints. On the other hand, I became less disappointed about the lack of animation. All I have to do is to regard VN as a kind of manga, only on optical media. When seen in that light, Hourglass is a compelling entertainment.

BTW, Sixten seems to explore the Ai avenue, but the events are all the same. But of course! Railroad plot.

This is the first professional visual novel I’ve played, and if other visual novels are this good, I can understand why they’re big among anime fans.

I think it's "manga fans" now. Compared to anime, VN is just not in the same league.