To be fair, that example was an Xbox 360 game so it's more of a 50% markup. Last gen games went for 60 Euros, this gen about half the Wii games are 50 (79$, including 12.5$ tax) the other half 60 (95$, including 15$ tax). DS games are 40 Euros (63$, including 10$ tax) for the full price ones, 30 Euros (47$, 7.5$ tax) for the budget ones (the ones that are announced as 20$ in the US AFAIK).
I know they assemble the Wii boxes in Europe so if they ship something it's probably just the discs which really shouldn't cost much. "Made in Japan".
Margins are most likely tiny if we go by the likelyhood of store-initiated pricedrops (near zero), some stores charge up to 5 Euros less per game and some go up to 3 Euros over the MSRP (up to 5 for Wii points cards which are never below 20 Euros and frequently above). We never get things like those "buy two, get one free" deals I hear about in the Amazing Deals thread. Getting a blanket discount of 20% on all videogames is close to a miracle (I've seen it as very short time promotions that ran 2-3 days and once for a store that was going out of business). Non-PC games are less likely to go into the bargain bin and especially games for Nintendo systems almost never drop in price (with a few exceptions you usually see these stay at full price until they disappear). I'd wager that as a result strongly budget limited but not well informed customers (e.g. kids) will get a disproportionate amount of crap on Nintendo systems (the first bargain bin titles on the Wii were Barnyard and Spongebob IIRC).