Yeah I love making circuits like that, but only if it's simple.
It gets really frustrating really quickly if you don't think VERY far ahead ;D!
Actually, I just looked at the first link in this thread and there's a photo of the underside of the protoboard. All the interconnects look metallic, but it would seem there's a lot of chances to get undesirable connections. Does anyone know if there's insulation around those wires or what they're made of? Or if this is advisable practice?
Those are indeed uninsulated wires (they look like component leads).
In a perfect world, you would use insulated wire for every connection, but in this case, as none of the wires cross each other, there is little chance of a short.
I mean, the metal isn't going to spontaneously melt and reach out to another piece of metal. It's going to sit like it is :).
As long as you make sure there's clearance between parts, you should be fine :).