It

On the DVD commentary track, the actors note that Tim Curry's characterization of Pennywise was so creepy and realistic that everyone avoided him during the filming.

It seems as if Mike was the last to join the seven back in the 1960s. The day Mike joins them was apparently several days after the other kids had encountered It. Out of the discussion about It, which takes place the day of the Rock Battle, we learn that every single kid in the gang has already seen It somewhere. However, later in the movie, Bev tells a story about the blood in her bathroom, and in the flashback, we see all of the 7 kids entering Bev's bathroom to clean the mess up, the day right after the blood had come out of the washbasin.

During the opening credits, we see pictures of the "Lucky Seven" from their childhood like in a photo album. The final photo of the Paramount cinema segues into the actual one in Derry. The camera pulls back from the title IT, and it turns from white to red. In Pt 2, the final photo of a hotel segues into the one the "Lucky Seven" are staying at. At the end of both parts, Pennywise's laugh is heard.

Although released on VHS and Laserdisc in the original two-part miniseries format, the DVD and Blu-ray releases from Warner Bros. are an edited Home Video Version which removes the end of Part 1 and the beginning of Part 2 in order to turn it into one long film. Here is what has been removed at timestamp 1:34:00 (the chapter 28 mark on the Blu-ray):

• THE END OF PART 1: Stan's wife finds that he has slit his wrist in the bathtub and starts to scream, the scream is cut off abruptly and therefore also the final showing of "IT" written in the blood on the bathroom wall, accompanied by Pennywise laughing and "to be continued" along with the end credits.
• THE BEGINNING OF PART 2: Starts with Bill arriving at the Derry cemetery. This completely cuts out his arrival at the hotel, the conversation with the woman at the desk, a short scene in his hotel room, the full ride in a taxi to the cemetery along with the opening credits.

Edited into Nostalgia Critic: Garfield: A Tail of Two Kitties (2017)