Advice on a custom lego build

[Shloogorgh]

So I recently discovered that someone made a lego version of Tarkus (from the ELP album of the same name). Tarkus is a giant mechanoid creature, part tank, part armadillo. The lego tarkus in question comes from http://www2p.biglobe.ne.jp/~s-hf/toy/lego/baka429.htm, a japanese website with no mention of specific parts used. I've found no other builds of the Tarkus, only the pics found on the japanese site. The only information I could find was that it seems to date to 2005.

I would love to try and make one (not exactly like this, as I'm not too fond of what they did with the shell, but everything else is spot on). Only problem is I haven't owned any legos since I was a child so I don't really know where to begin. Can anyone point me to any helpful resources?

I'm aware of the lego digital designer, which seems very helpful. It doesn't seem like it would have everything needed though. Any suggestions on how to get started? Can anyone identify some of the more unique looking pieces, like the swivel guns?

[Brickbuilder0937]

Bricklink is a great place to get parts if you know what you want.
The swivel gun is made from this part and two of these. The tread is made from this piece.