Continuity mistake: When Devon arrives to the CPR course for the Buy More employees he brings a CPR-doll and puts it down on the table. Yet, a second later it's right back in his arms in the same seemingly uncomfortable position as before.
Continuity mistake: Chuck thinks that his saliva can cure Casey, so he tries to kiss him. Casey tries to stop him and places his right hand on Chuck's shoulder. In the next shot, his hand is now on Chuck's neck.