The fallout from Saturday's title-decider rumbles on, with Police Scotland vowing "robust and swift" action against anybody found to have committed criminality after Celtic fans spilled onto the pitch following the final goal of their side's 3-1 win before confronting Hearts players in chaotic scenes.
Kyziridis had been one of Hearts' star players as they came within minutes of a draw that would have ended a 41-year wait for a team other than Glasgow giants Celtic and Rangers to win the Scottish title.
"From heaven to hell in 90 minutes. A story I will remember for the rest of my life, even though it didn't have a happy ending," the Greek posted on Instagram.
"I promise you this was only the beginning, and next year we will try again to achieve the best possible result."
Hearts condemned "deeply disturbing reports of serious physical and verbal abuse towards our players and staff" in a statement after the match.
Assistant Chief Constable Mark Sutherland said on Sunday that police investigations are ongoing.
"If any player, or indeed any member of the public, has been assaulted on that pitch, and there is criminality, we will take robust and swift action," said Sutherland.
There was also disorder in Glasgow city centre after the match, which Sutherland said left two police officers injured.
After Callum Osmand rolled in Celtic's decisive third goal deep into stoppage time, the match never restarted following a pitch invasion.
The Scottish Professional Football League (SPFL) confirmed that match was ended by the referee and not abandoned, which could have led to potential sanctions against Celtic that may have seen them stripped of the title.
"Given the speculation about the conclusion of the game, we would like to make clear that, prior to awarding the trophy, we were informed by the match referee that the match had ended and had not been abandoned," the SPFL said in a statement.
However, the governing body joined Hearts in condemning the post-match incidents.
"We utterly condemn the scenes which saw a number of Celtic supporters encroach onto the field of play," the SPFL statement added.
"We await the report of our match delegate regarding any specific incidents that took place but, regardless, supporters entering the field of play in any circumstances is wholly unacceptable and puts those participating and working at a match at risk."