Multilevel Game

Hi All,
I am struggling with a problem. I am building a multi level game in portrait mode.
I have one world where I want to have 25 scene. Each scene being 1 level. (Color Switch type game). I have put a menu jump at the end of the scene to take me back to the level selector menu. I have used lock buttons on the menu to take me to the next level.
The problems

1. The menu jump takes me back to the level selector menu... but the game seems to be running in the background and the character seems to be dying and that freezes the menu

2. The lock button doesn't get unlocked first time... ie... if I play level 1 and finish... level 2 doesnt get unlocked... but I go and play level 1 again... this time level 2 gets unlocked

3. I also want to be able to set a vertical speed for the background. I set the velocity and it only changes the horizontal velocity

Can you help

Regards
Jai
PS: I did not want to create a different world for each level as it would make the game heavy and difficult to manage I thought.

 

1) In menu jump settings, be sure to select 'Pause current world'

 

2) What I usually do is add a level complete menu that has a continue button. Add a 'unlock' button on top of the continue button and it will take the user to the next level.
So Menu Jump will go to the level complete menu and when the player clicks the continue it unlocks and starts the next level

 

Thanks Andre. The Pause current world is a good tip. (I guess I was being blind ).
I still am not clear on the following 2 points

1) I did not get the second tip you suggested. "Add a 'unlock' button on top of the continue button and it will take the user to the next level." - i.e. we add a navigation button that takes to the next scene on the level complete menu. We put a lock button on top of it and allow click through?

2) I am still not clear why the Level 2 unlocks after completing level 1 twice. Level 3 unlocks after traversing level 2 once ... but just level 2... it doesnt open up unless we play level 1 twice. I tried moving the checkpoint to the very beginning of the start scene ... even then it takes twice before the level 2 button gets enabled