From the way everyone was talking about it, I assumed it was, like. A TV series or something.

Nah it's a movie

Easy 90 minute watch

they are making another because they have a ton of story they want to tell

It was originally going to be a series but Sony execs weren't confident so they had to compact it down to a movie

hsumi: Proving, once again, that Sony's boardroom has no fucking clue.

Yup

Sony's mistake in handling this IP was so epic they don't even have the rights to it anymore

Also the surprise success of the movie was enough that they only just recently put out an artbook (digital only, physical coming later) and preorders for collector dolls (which sold out in a day; playline toys also reportedly coming later), despite the movie having come out half a year ago.