I would check to see that all of the blocks have been verified, as bad blocks can result in all sorts of nefarious problems. Choosing the correct block size will also help. If you choose blocks that are too small, you will be slowed down trying to fit everything optimally. If you choose blocks that are too big, you will waste space, most notably when you try to fit the Pi into a pocket or even a large-size Altoids tin.
At least you had the good sense to not try building it with Duplo blocks! :D
The best things in life aren't things ... but, a Pi comes pretty darned close!
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
In theory, theory & practice are the same - in practice, they aren't!!!