Of the 6 ongoing matches, only Real Madrid managed to close the first half with a 1-2 win over Napoli. Arsenal drew 1-1 against Lens, as did Manchester United vs Galatasaray. Inter, Sevilla and Bayern Munich all played goalless draws in the first half of their respective matches, but the favorite team still has a high probability of winning this match. Inter and Bayern Munich are likely to win, as are Manchester United and Arsenal, while Real Madrid vs Napoli could still change.
I was surprised that Copenhagen could hold Bayern Munich to a goalless draw in the first half, but two Premier League teams, namely Arsenal and Manchester United, failed to maintain their lead after taking the lead ahead of their opponents. Time to wait for the second half.
The score line still remain the same but there is a potential of having some surprising results in few minutes time especially in the match between PSV and Sevilla; Sevilla is trying to put more effort in order to prove other people that thinks they cannot qualify to the round of 16 wrong by given an outstanding performance in the match.
FC Copenhagen has scored against Bayern Munich which what almost all of us least expect because Bayern was the favorite in the match, but according to the way the match is going, I don't think they can win this match.
On the other hand, Napoli has gotten a penalty and Zielinski scored to level the score against Real Madrid. Real Madrid need to put more effort if they wants to win the match.
Currently Inter, Sevilla and Manchester United have taken the lead in their respective matches, while Bayern Munich managed to equalize the score at 1-1 by Jamal Musiala. You are right that some matches are difficult to predict even though on paper some of them are favorites.
Real Madrid has now regained the lead over Napoli when Valverde's rocket shot hit the crossbar before bouncing into the goal by Alex Meret's head. But this match looks like it has the potential to be a draw because Napoli seems to be really trying to equalize. There are still a few minutes before injury time, but Real Madrid also has a chance to close this away match with a win.
*I've been writing for too long so I've neglected how things have changed, especially in the Sevilla, Manchester United, Arsenal and Bayern Munich matches.