How Do You Like Loading Managed In Your Android Games?

So I currently have a game on the Play Store and one thing that has been bugging me is how to manage when the assets for the game are loaded. There are three scenarios I have programmed in, each with the upsides and downloads. If you could read each one and then post in the comments which one you would prefer I can hopefully get this loading of assets problem out of the way.

It's a puzzle/action physics game with around 27 levels in which each takes about 1-2 minutes to complete.

Scenario 1 - Complete Load At Game Open

So this one is pretty straight forward, when you open the game, it loads every asset the game will use. This means swapping between levels will only have a split second loading screen flash as no assets are being loaded only the level being set up.

Pros: One loading screen, after that there will be no more long waits

Cons: A 15-20 second wait (depending on device) before you even hit the main menu.

Scenario 2 - Per Level Group Loading

The levels are grouped together in lots of nine. They each introduce new game play elements, share some assets and have some unique ones. When you first load a level from each of the level sets, it checks whether the required assets are loaded, if not loads them and create the level. For example, a group 1 level is picked, it will check if asset group 1 is loaded, if not, loads them. A group 2 level is picked, it will check if both group 1+2 assets are loaded and load if needed and so on for each group.

So in summary, loads an entire groups assets at once and for each previous group.

Pros: After you load one level from each group, the loading screens will be instant and no long initial loading screen.

Cons: On the first level load, a 8 -10 second loading screen will be displayed. The later the level group, the longer the loading screen.

Scenario 3 - Per Level Loading

With this one, it only loads the assets required for that level.

Pros: The loading screens will be cut down to around 5-6 seconds per level, no long initial loading screen.

Cons: You will have to wait 5-6 seconds each level before playing

So these are the three scenarios I have for loading game assets. If you could pick one and post it below, you would be awesome... ;)