A very positive review of Mound Builders -- from Spain, in Spanish -- is found in the links elsewhere on this page (BGG won't let me post the link here).
"Mound Builders puts us in charge of the pre-Columbian culture of North America, from their growth and expansion, to its decline with the arrival of the Spaniards to the mainland. Like most VPG games, Mound Builders is available in a version with a box or a cheaper Zip bag. The latter is the one I have, because it ensures that the package won't be stopped upon arrival in Spain."
"Inside you will find a game map, 50 cards, 49 game markers/tokens, a 30 page color rulebook, and a support sheet, along with a funny little die that you will never use." :-)
"Overall quality is good, and the truth is that is quite noticeable as VPG is growing and learning by leaps and bounds in this regard. Perhaps they may never reach the levels of a larger company, but I think they are at a quite acceptable level and besides, we all know that what really matters is the game."
"Obviously, when one considers a bagged version price for under 20 euro, and you compare this to the prices of other games, you'll discover this one to be quite worthwhile."
"I found Mound Builders to be a great solitaire game, and above all, and most importantly, a challenge for the player. Some details are very careful (as the use of the peace pipe) and show great design work."