After struggling with a pair of bugs that were caused by the remains of debugging instructions I've managed to put the debouncing/detecting routines to work.

Now I have a global that stores the events related to the keys CLR, ENTER and Kyes 1-8.

// return value in key status: bit  7 6 5 4 3 2 1 0
//                                    | | | | \   /
// CLR long=1/short=0 ----------------+ | | |  \ /
// CLR event----------------------------+ | |   V
// ENTER event----------------------------+ |   |
// Key[1-8] event---------------------------+   |
// Key Pressed (1..8)---------------------------+

And here is a video of the detection working: