Very much on the easy side, but many people like those, as evidenced by their popularity. I don't know what the sphere did, I assume open the exit? I would suggest next time not make the map so large unless that's an integral part of the puzzle, it just makes the player walk a lot.

DISCLAIMER:
Read my profile before reading the rest of my comment!

Hiding links, being able to bypass intended ways to solve parts, unused test elements, and no immediately way to know how the exit door opens are all signs that the designer mistook what a puzzle is and thought a guessing game was a puzzle. That's where you are wrong:
http://www.cs2bus.com/sharedfiles/filedetails?id=292356592
http://www.cs2bus.com/workshop/discussions/-1/882949475710689142?appid=620

Try my SP map?
http://www.cs2bus.com/sharedfiles/filedetails?id=377129237
Try my COOP map?
http://www.cs2bus.com/sharedfiles/filedetails?id=376181211