I'm really digging Banjo Kazooie Nuts & Bolts. The difficulty/challenge really ramps up in this game. The first couple of hours- any challenge can more or less be beaten by making your car faster, which can be done by adding an engine or 4 to it. At ~25 hours, I think I'm 2/3s of the way done, and some of the challenges in the game now are real brain teasers.

Are you still playing, DarkGryphon? If so, you should add me on XBL (xhonzi) so we each have someone to compare scores with. So far, none of my friends have/play this game. Except for my wife, and I'm tired of beating my wife.