And take a closer look at the Mexican-styled pig mask that serves as the cover. While it's lying in a puddle of water, the only moisture on the mask's surface is at the corner of the eye, making it look as though the mask itself is weeping.
Just about everything about Mandus's relationship with his sons. They are his entire world and he clearly loves them both dearly, he even made the ill-fated trip to Mexico in part to ensure they would not be destitute due to his business's imminent collapse, and all throughout the game he repeatedly shows his willingness to dive head first into the unspeakable horrors of the Machine and the face both the army of Manpigs and the horrible implications of his own guilt in order to save them.... Which makes the revelation that he is not only far, far too late to save them but he himself personally killed them and tore their hearts out to fuel his machine an utter heartbreaker.
It's also revealed that Mandus has a bit of a love-hate relationship with his sons, since he promised his late wife that he would take care of them - but it's because of them that he's a widower to begin with.
Even this last factor is impossibly made even more tragic when you find out the main reason he did this. He saw their horrifying deaths in the Battle of the Somme in WW1 and was desperate to spare them this agony... so he decided to kill them himself. It is rare to see the concept of Papa Wolf be so horrifyingly and tragically deconstructed.
I love you my darlings and I am sorry. I am sorry for all I have done. I simply loved you all too much for this world.
The Engineer's Motive Rant seen in the Quotes Section. While an utterly horrifying entity who has committed terrible crimes against both man and nature and plans to turn the whole world into a stinking charnel house, his final Villainous Breakdown reveals how utterly broken he was by seeing the unspeakably bloody and nightmarish wars and genocides that the 20th century would bring and the countless innocents who will suffer and die because of this and how utterly desperate he is to "save" humanity from this fate.
Similarly, the first lines of the game are him saying "Daddy, please dont kill me!" as Mandus attempts to shut down the machine which indicate it is still just a child at heart.