Continuity mistake: When Alvin is making the big SOS sign, one shot shows the whole beach and Simon and Theodore are in the middle of the big letter O. In the next shot, they are at the O's edge.
Continuity mistake: When Simon is chasing after Alvin in the casino he jumps onto a tray being carried by a waitress. In the long shot the tray has two drinks one in a clear goblet and one in a tall red cup. However when he lands on the tray there is only a small clear glass with an orange beverage with a small blue umbrella, and a blue napkin.