"Principal filming for "Vienen" was shot at three different locations, including an oil rig, an oil refinery, and the show's set." Using the word 'Including' suggests it's only a part of the whole, I suggest removing it and using a colon to list it.
Production
"Usually, an episode of The X-Files took about 18 days to film. "Vienen," however, took only 11.", could do with a citation.
Plot
"Meanwhile, Dana Scully finds black oil in Simon's skull during an autopsy - but the oil is dead, as if irradiated.", remove hyphen and use en or em dash.
Reception
"The episode subsequently made its debut in Ireland and the United Kingdom on June 7th on Sky 1", remove the ordinal form of 7, per
WP:DATES and
WP:CONSISTENCY
"and was the sixth most watched television shows", plural needed?
"significant development inMulder and Scully's relationship", spot the joint word.
Should there be spacing in "B- rating"?
Footnotes
For ref 2, 'BBC Cult' is the work, BBC is the publisher.
"Principal filming for "Vienen" was shot at three different locations, including an oil rig, an oil refinery, and the show's set." Using the word 'Including' suggests it's only a part of the whole, I suggest removing it and using a colon to list it.
Production
"Usually, an episode of The X-Files took about 18 days to film. "Vienen," however, took only 11.", could do with a citation.
Plot
"Meanwhile, Dana Scully finds black oil in Simon's skull during an autopsy - but the oil is dead, as if irradiated.", remove hyphen and use en or em dash.
Reception
"The episode subsequently made its debut in Ireland and the United Kingdom on June 7th on Sky 1", remove the ordinal form of 7, per
WP:DATES and
WP:CONSISTENCY
"and was the sixth most watched television shows", plural needed?
"significant development inMulder and Scully's relationship", spot the joint word.
Should there be spacing in "B- rating"?
Footnotes
For ref 2, 'BBC Cult' is the work, BBC is the publisher.