I mean, it makes sense as an antipiracy measure, those who want to play part 2 have played part 1 and its asummed they have bought it; and its probably more convenient for when he releases the whole game, but a 40$ total price for a full game sold in 4 parts is a little too much.
		
		
	 
This has nothing to do with antipiracy (Otherwise they'll use some form of DRM)
It's just the DEV Overcharging / Overpricing. (
Expedition 33: Clair Obscur only cost $50, but this text-based VN charge $60 IF it comes with 4 parts.)
Like Modern devs split their games for parts then sell every part separately for more money.
Especially when every part charge the same amount of money, but Don't hv the same amount of contents. (PT1 is 400RMB while PT2 is only 150MB)
Yeah pretty scummy, but remember most Porn games nowadays charge $5-$25 per month for updates, and 5 years later they are still no where near finished.
It's just how the market goes, sadly. (Hence I rarely spend money here, even tho I buy games regularly)