Blooper

At the end of Chapter: 3 and beginning of Chapter: 4, the Mask floods the torpedo room with water to drown Spy Smasher. Submarines can't flood any part of a sub on purpose. If they flood the torpedo room, which is in the front of subs, it wound make the sub sink to the bottom and wouldn't be able to surface.

Chapter nine: You saw Jack puncture a hole in the "Armored Car". I don't believe it can be done, not with 1940s technology anyway.

In Chapter: 4, when Spy Smasher sneaks in to rescue the two men, after he swings down from the rope a gun shot can be heard. Nobody fires a gun at this time.

In Chapter: 3, when Spy Smasher rolls the tire with the gas can, right before the gas explodes you can see one of the movie crew moving away from the flaming gas can.