In the last scene when Clark and Ross are playing basketball, just before Clark jumps, their shadows are towards the left of screen, but when Clark is overhead, Ross' shadow is right, then both shadows revert to front (left) when Clark lands.
When Pete is talking about how Clark's downed spaceship is 'the Holy Grail' of stories, he says 'the Holy Grail' but his mouth repeats the words when the angle changes, without a sound. The same happens a few seconds later in the same scene, when Pete says "live it down".
When Clark and Chloe are walking towards school looking at the hospital visitor log (33 minute mark) you can see a large production light and a ladder.