I don't understand the tie breaker rules. Why are Italy number 1 in the group when their goal difference is worse than Spain and Croatia? And their mathces were all draws...
8.07 If two or more teams are equal on points on completion of the group matches, the following criteria are applied, in the order given; to determine the rankings:
a) higher number of points obtained in the matches among the teams in question;
b) superior goal difference in the matches among the teams in question (if more than two teams finish equal on points);
c) higher number of goals scored in the matches among the teams in question (if more than two teams finish equal on points);
d) superior goal difference in all the group matches;
e) higher number of goals scored in all the group matches;
f) position in the UEFA national team coefficient ranking system (see Annex I, paragraph 1.2.2);
g) fair play conduct of the teams (final tournament);
h) drawing of lots.
8.08 If two teams which have the same number of points, the same number of goals scored and conceded play their last group match against each other and are still equal at the end of that match, the ranking of the two teams in question is determined by kicks from the penalty mark (Article 16), provided no other teams within the group have the same number of points on completion of all group matches. Should more than two teams have the same number of points, the criteria listed under paragraph 8.07 apply.
So, based on all that, here are the rather cut-and-dry Group C scenarios:
SPAIN, ITALY WIN: Spain wins group. Italy finishes second.
CROATIA, ITALY WIN: Croatia wins group. Italy finishes second.
IRELAND DEFEATS/TIES ITALY: Spain, Croatia advance. Spain is first with win or draw; Croatia is first with win.
But the fun starts if Italy wins and Croatia and Spain tie, as all three teams will have five points.
ITALY WINS, SPAIN/CROATIA TIE, 0-0: Italy finishes first because of Rule C (Azzuri scored two goals total against Spain and Croatia; the others will finish with one goal total in such a scenario). Spain finishes second because of Rule D above (Spain 5-1 in goal differential in all matches, Croatia 4-2). NOTE: There have been no scoreless draws in Euro 2012.
ITALY WINS 1-0 OR 2-0, SPAIN/CROATIA TIE, 1-1: Spain finishes first because of Rule D (goal differential in all matches). Croatia finishes second because of Rule D (if Italy wins 1-0: goal differential) or Rule E (if Italy wins 2-0: higher number of goals).
ITALY WINS BY TWO, SCORES AT LEAST THREE, SPAIN/CROATIA TIE, 1-1: Spain finishes first because of Rule D (goal differential). With 3-1 win, Italy finishes second because of Rule F (Italy is higher in UEFA coefficient ranking system). With any two-goal win bigger than 3-1 (4-2, 5-3, etc.), Italy finishes second over Croatia because of Rule E (total goals scored).
ITALY WINS BY AT LEAST FOUR, SCORES AT LEAST FIVE, SPAIN/CROATIA TIE, 1-1: Italy finishes first because of Rule E (total goals scored). Spain finishes second over Croatia because of Rule D (goal differential).
ITALY WINS, SPAIN/CROATIA TIE, 2-2: Spain finishes first and Croatia finishes second, both because of Rule C (goals scored in the matches between the tied teams).