Stardock’s Jon Shafer has a great article on game design that has been spreading like wild-fire around the Internet.

With regards to the strategy genre in particular, restrictions on unit movement is one of the best examples of how limitations can make a game better. The inability of land units to enter water is why ships are so valuable – and just plain cool. Gaining access to new units with unique ‘powers’ is a major motivation for many players. Just like in economics, scarcity is what drives value – the fact that most units are unable to perform certain actions is what makes the few which can so much fun.

Movement restrictions also show that there’s a place for even permanent limits. An example from the Civ series is how mountains became impassable for the first time in Civ 4. It’s a subtle change that very few players would point to as a major innovation, but even something small like this helps breathe life into the map. Instead of mountain ranges being just another part of the map with a slight movement penalty, they suddenly transformed into true barriers that now require serious consideration.

Read the whole thing here.