That's BS, dude. It's 100 procent worth it if you don't like NTR the non-NTR route is really long. He saves his mom and even marries his mom and makes her pregnant the whole thing.
And even in some of the NTR scenes, the guy shares the mom with the son.
The sharing is still NTR my guy. The mom loves the bull but the bull being a "friend" and all, will let him have his sloppy seconds. Which the mom obliges cause she loves the bull and will do what he says and to a twisted degree "loves" her son giving him a pity fuck. There's no polyamory or throuple situation. The MC gets to fuck his mom only on the bulls say so.
There's 3 routes. Full NTR, NTR + sharing, and non-NTR. Yeah in most cases that'd be a 1/3 split between the routes, but the game is first and foremost an NTR game with 2 routes being NTR focused which is why instead of the non-NTR route getting a third of the games playtime it'd probably be more close to a fourth.
Which is why I'm saying it's not really worth the download if you don't like NTR as you're only getting at best 25-33% of the game. Why play a game where the vanila route was the afterthought if that's what you're looking for. There's numerous other incest VN's where the mom fucking is the full focus and you get way more content.