So I was lurking everywhere to find a great game to entertain me, and I found it : IntoSpaces !
Long story short, you incarnate a mad scientist who want to reach the moon with a rocket. I know that they are many games who have the same storyboard, but with this one, you will not only be able to upgrade your rocket, but as you progress in the game, you win achievement who help you to reach your goal.
Here is my fantastic rocket !
And the few bonuses I've earned so far.
If you're looking for a time killer, this is the perfect game ! You will need many hours to finish it.