Hmm, well, you could add a global variable, call it something like level. Then use:
System: Compare: Enemy.Count equals 0
- Global: Add 1 to level
- Go to layout global('level')
and make sure the variable level is set properly at the start of the game (its initial value can be changed in the project view).
Hmm.. if you have your layouts named logically, Level 1, Level 2, Level 3, [...] Level 10, Level 11, etc., you could do this instead:
System: Compare: Enemy.Count equals 0
- Global: Add 1 to level
- Go to layout "Level " & global('level')
OR, instead, an alternative, hackish, probably unnecessarily complex way to do it, one I'd recommend against unless all else fails:
You could place an object named LevelInfo on each level, outside the visible play area, or just invisible.. with its own private string variable, NextLevel, and for a value use the name of the next layout, like Level 1's LevelInfo would have the value "Level 2". Then copy your LevelInfo object. Go to layout Level 2, and paste it, then change the variable value to "Level 3", etc.
Then you'd use: Go to layout LevelInfo.value('NextLevel')
There's surely a better way to do it than this last one, though.