Tower efficiency visualization

Tower defense strategy is all about placing towers at strategically right positions at right time. The spatial strategy is quite clear by looking at the map. But the temporal strategy is not. In other words, it's not obvious how the tower performs over a span of time. Or among all towers which tower is performing to max efficiency and which is not. Here efficiency is defined the fraction of total time that the tower spends actively firing at the enemy. If it has lower efficiency, then that means the tower is placed farther away from the main enemy path and may not be worth the resources put into it (however that's not always necessarily true. Some towers are placed just to push enemy away from them and take longer paths).

The new feature, as should be evident from the screenshot gives you just this information. You turn it on by clicking on a button in the tray near right bottom of the screen.