Mud and Leaves
Here you can see that there is not only the gravel that is supposed to help with drainage in the window well but also a decent amount of leaves and mud built up over the years. If you look really closely you can even see evidence of new growth I'm guessing from a seed that fell down last year at some point.
Dirt in the window well
In this photo you can see pretty clearly that this window well is no longer draining. Notice the sand, dirt, plastic and new tree growing this is not how a window well should look however it is how many do look. Window wells such as this one will not drain properly, this could lead to the window well filling up (looking like a fish tank from the inside) and may cause it to leak into the basement.