These are all based on the box being sealed. I'm not going to open as I'm trying to return the KO and assume I'll have to send it back in the condition I received it.
Here we go:
1) Vintage box is a much darker purple color throughout
2) Small writing on bottom front of box: Vintage reads "Ages 6 and up *long space* For longer life, use 9 volt alkaline battery (Not included)"; Knock off reads "Ages 5 and up *no space* Includes snap-on weapons & accessories. For longer life, use 9 volt alkaline battery (not included)."
3)Hasbro stamps are different: On vintage box, stamp does not fill up the 4 "grid spaces" and has no white outline; knockoff box does fill up the 4 "grid squares" squares due to a white outline.
5) Different fonts for the "Transforms from laser gun to robot and back!" section above window.
6) Different size "TM" above the "S" in Transformers on the flap.
7) Grid lines and printing: On vintage box, grid lines are white and there is crisp coloring around the "Decepticon Operations: Shockwave" box. On knock-off. grid lines are almost a light greenish color the color bleeds on the Shockwave name band.

9) Gun barrel: Vintage - barrel clearly covers entire length of hand section; on KO it ends just before the arm so you can see some of the clear purple plastic on the hands).
10) My KO has no rub-sign, although I know many do have the rub-sign.
11) Black screw in the grip on the vintage figure; silver screw in the grip on KO.
12) On back of vintage box; Megatron's foot is covered up in the lower right corner by the UPC; on the KO box, Megatron's foot is not covered.
13) The trademark stamp in small letters on back left of box: On vintage, middle section reads "Made and Printed in Korea"; KO reads "Made and Opened in Korea."
14) In upper right corner of box, the "It is a world transformed..." section are different fonts and size. Also, on the KO box there is no space between "where things" in the second line; i.e. it reads "wherethings are not..."
Hope this is helpful. Let me know if there are any questions. I'll try and post some pics later on.