According to the DOOM FAQ:
[5]: What are the differences between the different releases of DOOM?
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(5-1): What is the shareware release?
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The shareware version of DOOM only includes one of the three missions of DOOM. Each mission contains eight levels and a secret level. The shareware version contains network support and modem support. The shareware version does NOT include the Plasma Rifle and the BFG9000 weapons. On December 10th, 1993, v1.0 was released. On December 16th, 1993, v1.1 was released. On February 17th, 1994, id released v1.2 of DOOM. This version fixed many bugs and added new features, including modem support. Unfortunately, this revision added many new bugs. Finally, in June of 1994, v1.4 was released. This version was only an "Internet Beta version," as was used to find bugs before the pending released of v1.5 of DOOM. Then, on July 8th, 1994, v1.5 was released as another "Internet Beta version." Both version 1.4 and 1.5 were released without registered version patches. In early August, v1.6 was released as yet another "Internet Beta version." FINALLY! In early September of 1994, v1.666 made its debut! The new features of 1.4, 1.5, and v1.666 are outlined in Chapter [5-3].
So yes - it is 10....
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When the going gets tough...the tough get gibbed!