Max relies upon Barnhill's assertion that that he climbed Kilimanjaro to prove that he knows how to use rock climbing equipment. It is possible to hike to the top of Kilimanjaro without doing any technical rock climbing.
The goof item below may give away important plot points.
Towards the end of the movie when Max Grabelski was trying to untie Gordy's mom. While Max was trying to figure out what knot was keeping Gordy's mom tied up, Reinhart Bragdon then walks in saying it was a "Clove hitch." A Clove hitch is meant to secure a rope to a solid circular pole of some sort. If tied to a soft non-cylindrical object, such as human flesh, it would loosen up quite easily.