Difficulty Levels

```
What Feature would you like us to add?

Add difficultly levels to vary the number of obstacles, aircraft, time etc 
depending on what the user selects when the game starts.

Have Easy, Medium and Hard Levels.

Read the values in from different config files.


```

Original issue reported on code.google.com by `scotty3...@gmail.com` on 29 Mar 2011 at 1:52
