Last week, American tanks rolled into Denmark and the Stars and Stripes were hoisted over a park in downtown Copenhagen. But you will not have seen this particular invasion on the news. It happened in the pixelated world of the video game Minecraft.

Minecraft is an oddity in today’s games industry, where there are two shortcuts to making a smash hit. The first is to develop a smartphone or tablet game whose simple puzzles get dramatically harder after a few hours. The developer can make the game itself free, then tempt players to pay up when they get stuck on a tricky level and want to skip ahead. This is the business model behind King, maker of Candy Crush, and Zynga, creator of FarmVille.

The second approach is to spend millions on a console game with a huge marketing budget, high-tech graphics and perhaps even some Hollywood talent (Kevin Spacey stars in the latest Call of Duty). It is a high-risk strategy with potentially high rewards: Grand Theft Auto 5 clocked up $1bn in sales in its first three days when it was released last September.