I just finished Driftmoon, and at the end, it talks about a giant snowman and a severed hand named Mitten. I don't remember any of this. Do I have Alzheimer's?

I need to replay this. The snowman and mitten is familiar.

The mitten I think was early in the game. The snowman is less familiar though. I think it was towards the latter half something to do with a lighthouse.

Both are familiar but exacts are a bit iffy. There was a walkthrough or something posted not long after full release which should have the specifics.

I really need to replay this. So much of it I cant put in the right order etc.

Yes, there was such things. Severed arm is one of early bosses you fight to get ring with infrared vision. Its actually real hand revived by cursed gem
Giant snowman is monster send by main bad guy to freeze that town where you encounter mechanic girl.

Mitten is the hand that the farmer with the Hoe of Doom accidentally cut off.