Sloping floors driving me crazy!

Sorry if I'm posting this in the wrong forum since I am new to the DIY forums. If it is in the wrong place please direct me, thanks. Background: 15 year old house. I just bought it, it is my first house purchase. Slab on grade foundation House sits on top of a hill, back of the house sits very close to steep hill drop. A few months ago we bought our first house. It sits on top of a hill, and the backyard dramatically slopes down starting within just a few feet of the end of the house. The house has an incredible wood deck all along the back, which allows us to look out over the wooded area. The wood deck is supported by concrete pillars driven into the ground. I am usually one of the most observant people you will ever meet.....if I detect something is wrong, I will usually pick up on it before most people will. However, I think in this instance, and maybe because I was caught up in the whole house buying process, this one slipped past me. During the walk through of our house, I never noticed any sloping to the floors.....but I really wasn't thinking about looking for those kinds of things when you're first going through a house. I naturally was looking at the general feel and look of the house. The house was completely empty as well with no furniture, so I don't know if that helped play into the fact I didn't notice any sloping floors. I did notice however during the tour some oddly added concrete that looked like it had been added under the back of the house after the original construction. I did look odd and concerning, but for some reason I didn't red flag it. I will try to post of a picture of it.