E is the twenty-first level of More Bloons.
To complete this level, you need to pop the Spiky Bloon, so that it can pop the Tack Bloon on the bottom, which will pop some bloons. Next, pop the Tack Bloon on the bottom right of the monkey. In case of remaining darts and you still need to pop bloons, then pop the bloons with the remaining darts until you reach the target.
- Hence the level's name, the bloons are placed so that they can form a giant letter E.