Ending of 13 Beloved

So I watched the original before this one and just wondered why so many people were confused/disliked the original ending?

The dad won the game due to killing his son as his final challenge and his other challenges were briefly seen in the flashbacks (smashing his sons toy plane, killing his dog etc). I'm guessing the reason the guy didn't stab his son immediately and pretended to be unconscious was due to it being part of his challenge to do it that way in order to make the game more exciting to the viewers though I admit I'm a little confused as to what he was doing all those years before his son got into the game.

The kid at the computer was just one employee making sure Tongs game went smoothly as he says there are many games taking place at same time presumably all ran by different people but under one company/organisation.

The thing I liked most about the original ending is when the woman says "You killed him" and the kid saying "We killed him" back which is pretty much true since if it wasn't for her intervening Tong wouldn't of regained some of his humanity (as shown in the "choose to kill the dog or her" scene) and would of instead had a different challenge which would of pushed him away further away from his humanity resulting in Tong being able to kill his dad instead of getting stabbed himself.

The confusion might be due to the very last scene where they just left the woman on a bench somewhere instead of killing her since the game runners seemed pretty annoyed Tong left her alive and killed the dog instead (Though they might of just been mad at him regaining some humanity rather than her still being alive) but yeah, you'd think they would of just killed her after the game had ended even if she can't do anything about it with the game runners owning the police there's still no point of keeping her alive unless to be part of someone else's game

I really didn't see the ending coming which is a rare thing in films nowadays and I liked the twist personally though these are just my thoughts and I'm curious as to what other people that have seen the original ending have to say about it.