Many games on the App Store only found success after an initial mis-step; Doodle Jump and Angry Birds are two that spring to mind.

Spooky House Studios' Rail Maze isn't quite as successful, yet.

Originally launched as Doodle Train in March, it didn't catch the public's imagination. So the team went back to the drawing board and re-styled the art.

Tear it up, start again

The result was Rail Maze, a game that's been #1 in 31 countries including the US, UK and Germany, and downloaded 4.5 million times on the App Store and 500,000 on the Mac Store in a month.

Of course, it should be pointed out that the other significant change with the re-release was a change of business model with the previously 99c game going free.

Still, 5 million downloads is a useful platform to build on, something Spooky House is doing in terms of IAP and cross promotion with its other apps.

It will also release a new level pack for Rail Maze in a couple of weeks.