There are some similar forum posts out there that have somewhat clarified part of my issue here - I now understand the difference between On Key Down and On Key Pressed. The latter waits for the release of the key.
MY present issue is that I simply want to have an Action take place when the Event tests that a key has been pressed at all, regardless if the key is held down or released...or not. Just, was it pressed.
My scenario is that I have a character who will throw a punch upon the K key being pressed. The Action that ought to follow is that the Punch animation will play...from start to finish, all six frames. However, whether I use either On Key Down or On Key Pressed, the animation is immediately interrupted when I let go of the key.
(I've tried setting up a work-around - and almost got it "perfected" - but it's too lengthy to try to explain.)
So, ultimately, what I want to happen is this...
1) I tap the K key and quickly release...
(SIDE NOTE: Presently, pending a solution, I can hold it down, whether by O.K. Down or O.K. Pressed, and the animation repeats until I release the key.)
2) ...The punch then plays through a full sequence once regardless of the current true/false of the K key press in subsequent frames.
I've made sure the Loop is set to No on the animation sequence. I've also tested On Key Released. None of them work for my desired result.
Thank you for your help!