The race is the Netherlands' largest professional race but is frequently criticised for the danger of its course. The Netherlands is a densely populated country and the race runs through many suburbs and villages. With pressure on land being so great, many Dutch houses do not have garages and cars are left parked in the street. There are also many traffic-calming obstacles such as pinches, chicanes and speed humps, and further obstacles such as roundabouts and traffic islands. Crashes are not uncommon in the race.
The course is tough and selective, mainly because of the 31 hills that have to be climbed, some with angles as steep as 20% (Keutenberg). The Amstel can be confusing for first time riders, because the course features a lot of turns, plus some spots are visited more than one time during the race.
Velonews summarized the race in 2009 as follows:
This is the mack-daddy race on the Dutch calendar. It’s Holland’s most important event and Dutch [teams do their] best to try to dominate the demanding, 258.6km course... Held in the hilly Limburg region in southern Holland, Amstel Gold often gets bundled with next week’s Flèche and Liège races to create what pundits like to call “Ardennes week.” Though geographically distinct than the nearby Belgian Ardennes, the Limburg region serves up a similarly endless menu of steep, narrow climbs. Any race named after a beer should be a big party and tens of thousands of beer-guzzling Dutch fans turn up to line the endless string of bergs and clog outdoor beer gardens to cheer on the pack as they ply treacherously narrow roads. The course starts in the main square at Maastricht and, since 2003, ends atop the Cauberg climb just above Valkenburg (site of another huge party). The route map looks like a plate of spaghetti, with four loops tracing back and forth over deceptively steep climbs. An endless string of 31 climbs are wickedly steep, with Keutenberg featuring ramps as steep as 20 percent. Coupled with the narrow roads, strong winds and the danger of crashing, Amstel is one of the season’s most nerve-wracking races. The addition of the Cauberg finish dramatically altered the race dynamics. The finish used to be on the flats alongside the Maas River, giving teams a chance to regroup after the last climb and position their sprinters for a sometimes-large group sprint. [It now favors whippet-thin climbers and hilly course specialists.]
Attempting to explain the difficulty of the course Peter Easton recounts a mathematician's calculations:
...applying logic to overcome a sense of incomprehension is the key to understanding this race. And there is truth in numbers. Six of the climbs come in the first 92 kilometers - one every 15.2 kilometers. The remaining 25 come over the final 165 kilometers. That’s one every 6.6 kilometers. Breaking it down further, the final hour of racing has eight climbs in 42 kilometers. Now we’re down to one every 5.25 km. At 40 km/h, that’s one every 7 ½ minutes. Not overly funny, and definitely all business. 
The current hills in the Amstel Gold Race are