(USA) To be out in left field is not to know what's going on. Taken from baseball, when youngsters assign less capable players to the outfield where the ball is less likely to be hit by a young player. In business, one might say, 'Don't ask the new manager; he's out in left field and doesn't know any answers yet.'
(UK) If someone does a Devon Loch, they fail when they were very close to winning. Devon Loch was a horse that collapsed just short of the winning line of the Grand National race.
(UK) If something's a game of two halves, it means that it's possible for someone's fortunes or luck to change and the person who's winning could end up a loser.
In American football, a Hail Mary pass is a long, desperate pass at the end of the game that is hoped may gain some points, so it is used for a desperate attempt to resolve a serious problem at the last minute.
If someone hits the bull's-eye, they are exactly right about something or achieve the best result possible.
"Bulls-eye" and "bullseye" are alternative spellings.