Aw, dayum, that was pretty intense! I loved it! Especially the whole concept that Jimmy not speaking/Jimmy not caring went hand in hand, and then when he started talking he started to actually feel bad about what he did. The whole thing was moving, in a creepy, awesome kind of way xD
And the reveal at the end, aagh, nooo! I kind of had the inkling that something had happened to his girlfriend and kid but noo! Poor, insane Jimbo.
Ooh, and the 'I am the cause' at the end was brilliant after all the repetition earlier on in the story, it hits you pretty hard, it was really well done.
All in all, awesomely done, haha!