1) When you turn the ball over four times and don't force any, you generally lose.
One interception led directly to points for Northwestern. A second killed a promising drive. A fumbled snap killed a third at the goal line (though it did lead to two points). And a fumble at the end of a long catch stalled us out again. You're not going to get away with that against even mediocre teams, and Northwestern is better than mediocre.
2) Where did the aggressive coaching staff of the past two years go?
One thing that went somewhat under the radar during the last two years is that Dantonio wasn't afraid to go for it on 4th down when the situation called for it. The punt with three minutes left on 4th and 8, down 3, nearly in FG range, was utterly indefensible. Best case scenario, you're starting over from a similar spot with no timeouts and 20 seconds knocked off the clock. If Northwestern gains any first downs or gains more yardage on their punt than you do (which is likely since you have only 40 yards or so to work with), you're in much worse shape.
(And no, the announcers who defended it as the "percentage play" were not correct. At that place on the field, going for it would be defensible in the first quarter. Trailing late in the fourth, it's absolutely mandatory.)
3) Bad day for the receivers again.
Numerous drops, including two on the desperation four-and-out, killed drives left and right. Dion Sims stood out with a solid day (5 catches, 102 yards, about six guys to tackle him each time), but even he had a key drop (couldn't hang on when he got hit for what would have been a first down on the last-ditch drive). Andrew Maxwell isn't blameless for the offense's struggles either, but his stat line would be respectable enough if the multiple deep passes that hit receivers in the hands were caught. And to further spread the blame around, the pass protection had several critical breakdowns - it doesn't matter who the quarterback is if two guys are breathing down his neck by the time he finishes his dropback.
4) Big Ten referees are incompetent, but you knew that already.
For the third time in Big Ten play, MSU had a touchdown taken off the board by a bad call (although this one was only "probably wrong" instead of "obviously wrong"). Bell got the ball across the goal line on 3rd and goal in the middle of the second quarter but was ruled down short of the goal line. Replay showed his legs at an angle inconsistent with his knees being down, but you couldn't actually see his knees and so the replay booth couldn't overturn it. On 4th down, Bell got tackled for a loss. With every game being decided by 4 points or less, taking 7 off the board is obviously a big deal.
It also doesn't help that an obvious pass interference penalty went uncalled on the last-ditch desperation drive on 3rd down. We would still have had 30+ yards to go to get in field goal range, so it likely wouldn't have mattered, but given how our previous game ended, that's really just adding insult to injury.
I don't like to complain about referees, but they've been an absolute horrorshow in conference all year long, and not just in MSU games. (Ask Penn State fans about their game against Nebraska - preferably from out of throwing range.) The fact that we've had so many close games simply magnifies their impact.
5) One more chance to get to a bowl game.
Beat Minnesota and a bowl destination in Arizona or Texas awaits. And it's obvious we need the extra practices.