An inability to just...stop typing? 🤣🤣
No, in all seriousness. It's really about love interest amount and branching usually. All games have a inherent structure to them. A shape you can visualise through something like flowcharts if you want to. Writing the game is like revealing that shape, little by little. As a writer, I'm currently half-planner and half-pantser which means I like to let a large portion of the story develop organically as I write. This means I know the story going in but the 'shape' of the game is a mystery.
With GS, though I did go over my target word count by a lot, it was largely due to the three additional LIs. I think I originally said 600k for that game but I knew it would probably be closer to Changeling's length (686k). I didn't want to promise 700k if I couldn't get there so I went with 600k instead. But I did know that game would be more like 675k+. And actually the original six LIs were right at 700k. So that was within the ballpark. The game went over 1,000,000 purely due to the additional LIs. I had difficulty pinning down an *exact* amount but with games this size, honestly, within 50k is definitely a pretty good estimate. I thought it would end up at around 990,000 words and it ended up at 1,037,000 words so I consider my estimate for that game pretty accurate.
With Changeling, it was my first game and I really did not have any idea how to predict anything. I knew what I wanted in terms of hours but had no idea how to translate that to a word count. And at the time, in the VN dev community you couldn't get a straight answer on that topic. Now the community is bigger and it's a little easier to suss out how to convert between play time and word count. So with Changeling I started out thinking I'd hit about 300k but realised that was too short for the amount of love interests and size of story I was aiming for. So I adjusted the word count up to 500k. I was thinking about 75k per route + 50k for a common route. But my issue there was not accounting for any choice branches or endings.
The routes in Changeling *are* about 75,000 words...if you don't count the choices and endings. So I was kind of right...but also not really. Ha ha.
With WSC the issue is completely different. I've never written a game structured this way before and I cannot express to people how *different* it is from the usual structure I use and how hard that made it to predict anything about this game. It was a completely unique experience for me. Where the word count tends to balloon unexpectedly is really the branching and variations...and unexpected love interests popping up. I really did not have a feel for the "shape" of this type of game. I added a love interest. I couldn't predict the branching at all. All of those things combined made it really hard to estimate where this one would end up.
I wanted it to be 300k but realised fast that with that structure, it was going to feel rushed. So I bumped the word count up to 450-500k as the target, thinking that would give me more space to expand the story and slow things down a little. And then I added Kav. So...ㄟ(≧◇≦)ㄏ
This game, more than any other so far, I wasn't able to grasp the "shape" of what I was constructing as I wrote it and that was probably the biggest reason I could never estimate where it was going to end up.