This is a direct port of the demo map found in the PC Gamer Minecraft Demo, it's made to be playable on minecraft full release 1.2 to 1.7 full release (and any future version if mojang doesn't change the world generation algotherms).

Points of interest *spoiler alert* :

• PC Gamer changed the following to the world: 53 red wool, 90 snow blocks, 112 black wool, 3 chests, a sign, 22 gunpowder, a nearly broken iron pickaxe, a nearly broken iron axe, a nearly broken flint and steel, 4 coal, 5 bread, 4 string, 12 torches, 2 sticks, and 3 compasses.
  
• If you dig directly underneath the sign telling you how to open the chest, you can find a chest that contains 22 gunpowder.
  
• If you look hard enough, way out from the spawn point, in a desert, there is a chest with a saddle and other necessities. The chest is blocking a small spring from flowing all the way.
  
• If a player goes left when they reach the PC Gamer sign, they will find a skeleton dungeon.
  
• If you dig straight down at the spawn point, at bedrock level, there is 1 diamond.
  
• The giant "PC Gamer" logo is found across the lake from the starting area.
  
• The demo spawns the player atx=166.5 y=65.6 z=-56.5.
  

Additional Notes

The seed will only work for minecraft Beta 1.3, and will obviously not have the pc gamer logo pixel art, easter eggs and chests placed there by the pc gamer team.

I can't put a space in between the 'at' and 'x' in the last line of points of interest. And yes I even tried unicode ALT+255.(PMC bug?)