I think the best way to look at this is through actual numbers. Right now, based on the gallery, the game has 376 scenes. These aren’t reused assets or slight variations of the same content. Every one is a fully original frame with unique artwork. Honestly, I can only think of a couple of other games on this entire site that offer this much content.
Saying the whole game takes 3 hours to finish feels like a big understatement, especially if you're starting from the very beginning. Even if you spent just 3 minutes on each of the 376 scenes, that alone would add up to about 18 hours. And that doesn’t even include gameplay sections, regular dialogue, or anything else between the main events. If you play the game normally without holding Ctrl to skip through everything, you could easily spend over 24 hours finishing it.
By the way, I recommend picking the cheat mode at the very start. Some parts of the game are a bit unbalanced, and the cheats help you skip the more frustrating moments. You won’t miss out on any of the good content by doing that.