Checking it every 30 seconds is causing the problem. Remove that from the events and it should work.
The way you have it set it will always go to Retry level because it will send you there before you ever reach 12 points. Use a different trigger to check your score like on player dead.
Set a global variable and call it EnemyCreated and one called EnemyKilled
Each time an enemy is created add 1 to EnemyCreated and when an enemy is killed add 1 to EnemyKilled.
Every tick check to see if they are equal and if so then all enemies have been killed.
If you are spawning enemies continually you will need to stop spawning while you check if all enemies are dead.