While I fundamentally agree with you about the lineage, I can appreciate that there is a direct thread of artistically psychotic surrealism in Squid Game that feels inherited from Battle Royale.
The pink caskets (which might be my favourite visual element) feel like they would be at home in the world of Battle Royale, but IMO feel way too dark humor for Hunger Games.
Battle Royale and Squid Game both feature characters reaching quivering ecstacy when players die. My memory could be rose colored at this point, but Hunger Games just wasn't that dark.
I always thought of Hunger Games as Battle Royale for children. The violence and darkness in general is so very stripped down. IMO that's what made Battle Royale and, as you point out, Squid Game interesting. I do think that's more common in Asian cinema and tv though.
There are several characters in the first Hunger Games that revel in the death of their competitors, including several that torture their victims to death. A number of the competitors go into the games knowing what they involve, having specifically trained to kill other children.
In the second and third Hunger Games novels, the traps and obstacles are designed to torture, maim, and/or inflict painful deaths, for the viewing pleasure of those watching (in the second) or just to inflict pain (in the third). At the end of the final novel, the "good" guys murder a bunch of innocent civilians (including children) in order to assure their ascendancy to power.
In terms of darkness, the Hunger Games is darker than Battle Royale. But it's not a direct comparison, since Battle Royale is a satire and Hunger Games is not.
As a white male American, I've sort of started to realize that 'asian' media plays with life/death more than american media, which seems to simply delineate: life = good; death = bad instead of exploring the notion of acceptance.
The pink caskets (which might be my favourite visual element) feel like they would be at home in the world of Battle Royale, but IMO feel way too dark humor for Hunger Games.
Battle Royale and Squid Game both feature characters reaching quivering ecstacy when players die. My memory could be rose colored at this point, but Hunger Games just wasn't that dark.