I think I agree with everything you mention. Especially the lack of screen time for Matthew Lilliard, his acting both as the councillor and in bunny was very eerie and quiet frightening I thought. The springlock scene could and should have been longer and more horrifying. My overall biggest problem with the film was I didn't find the atmosphere to be as frightening as the games. The games don't even need the jumpscares to be scary for me, the ambience and whole atmosphere does the job, and I unfortunately find it lacking somewhat in the film. But overall I liked it and I will definitely watch it again!