παίκτης / παίχτης
In a recent exercise, the latter was identified as a typo. (And there was no button for "Discussion" to beef about it!)
Both [παίκτες/παιχτες] are now accepted on all sentences.
Here's an idea. Since the creators of the course are all non-professional course creators who have volunteered to help bring Greek to the public and been chosen by Duolingo based on academic and other qualifications, of course, we are always grateful for input from the community and have seen essential improvements in the course through it.
So, let's say instead of "beefing" you simply inform the mods and we will be more than happy to make any edits required. And grateful for the addition to the course.
Here's a lingot for catching a missing word. Thank you.
Was this part of a longer sentence, or just this word (i.e. "Write 'the player' in Greek") with a corresponding picture? I'm asking because "no button for 'Discussion'" sounds like one of those questions which are automatically generated by the DuoBot (all other questions have a 'Discuss' button, as far as I know). If so, the mods have no influence over the accepted answers. The 'Report" button is also not helpful, since it only has "The pictures do not match the given word." option. In my experience these questions generated by the DuoBot accept only one answer - so in problematic cases one just has to remember the expected answer for the next time the question comes around.
With Type what you hear exercises you also have to be very exact with your spelling (e.g. if the audio has παίκτης, then παίχτης will not be accepted), but these questions should have a 'Discuss' button.
Finally, the missing 'Discuss' button could have simply been a glitch. Then it would be easier for the moderators to solve the problem if you quote the complete sentence and maybe even post a screenshot.