Prisoner Cat has high health (1,500,000) and high damage (12,000). However, he has a big blind spot and, as a result, cannot hit enemies right in front of him.
Turn the animation on and off using the switch in the upper left. Clicking the viewer background enables scrolling and zooming with the mouse if on desktop. Note that browser zoom may cause issues with scrolling and zooming. A list of available backgrounds can be found here. For more info on usage, see here.