At the end, you may notice that his legs get stuck together like an imperial walker during the battle of Hoth! Ah, memories.
The instructions in the manual indicate very clearly that the nuts should be placed on the inside of the leg - presumably for aesthetic reasons. However, the short section of bolt which sticks out of the inside has a nasty habit of getting hooked on the opposite foot.
If you can tolerate your robot looking a bit road warrior themed, I suggest reversing the direction of the bolts to avoid having your robot flail about like a memermaid, and also the internal damage to the plastic casing:
I do often complain about the robobuilder design, but I think I should make it clear that I am by no means unhappy with it. These are small complaints which (I hope) will be addressed by the robobuilder community and also allow others to avoid my mistakes.
The wCK servos are actually the best robotics servos I've used for their price. You can skip the durability issues I've been having, simply by getting the wCK 1111 version, which has 3 metal gears and a higher torque! They have a suite of extra features, such as brake mode, 10bit positioning (360/1024 = 0.35 degree accuracy!), runtime adjustable PID settings, continuous rotation mode, and the ability to write simple programs to run on the servos themselves.
I have yet to use these features, but I can already think of a thousand uses for them.