Kling is described as 'A utility to show keyboard keys visually on the Windows screen. - KaustubhPatange/Kling' and is an app. There are more than 10 alternatives to Kling for Windows, Mac, Linux and Xfce. The best alternative is Carnac, which is both free and Open Source. Other great apps like Kling are Screenkey, KeyCastr, KeyCastOW and Key-mon.
A Little utility that implements a global key logger which displays all shortcuts & keystrokes as you type on screen and with a semi-transparent overlay. This makes it very easy to show any shortcuts you use if you for example record a software demo.
KeyPress OSD is a full-featured screencasting tool for displaying key-presses on Windows. Beyond on-screen keypress display, it features text-expansion, mouse-highlighting and a multi-clipboard manager.
Visualize allows you to highlight your key presses and mouse clicks right on your desktop! The perfect tool for presentations or video tutorials, Visualize allows you to customize the look so your viewers can follow along with ease.