Penguin Adventure Slot Machines

Not entirely. Once you get one right it is a question of timing. ld a,r is a refresh counter and it is not so random as we like to believe it is. It just counts really fast. So if you are good and fast enough its not just luck. Only the first one is.

The human brain is pretty capable of doing some damn precise timing so if you have practiced enough you may have increased your chances significantly to get 3 in a row.

Daemos is right about the R register. It is incremented once per M1 (or so, I'm not sure). Its lower 7 bits work somehow like a counter.

The problem here is that every iteration of the program does not execute the same number of instructions, so R register will not be incremented with a constant value (i.e.: the music player does not execute always the same instructions in the same order and with the same results)

So in each iteration R will have a different value, so the array will start at a different point.
Furthermore, each time you select an item in the slot machine, the loop that updates the 3 positions is decremented, so the R register again is updated different in each iteration.

Also the slot machine is updated 50/60 times per second. So, for a human, I think it is matter of luck.

we should be very carefull with that statement. There is a japanese guy who actually cuts bullets in half with the size of a peanut comming at him at about 110-130 m/s which is faster than the human eye/brain combo can actually proces the incomming images. He even draws the katana which is a proces subject to friction and other physics as well.

A well trained human can reach to pretty exsessive performance if it is about timing.

I figured the result array perhaps being independent from what's displayed when the reels are spinning... Like the actual outcome was determined only when pressing space, like a random value picked from the array at that time..

So actually the reel is spinning the values from this array, and when space is pressed it stops right there?