My slide automatically pauses after a few seconds and doesn't display the other objects that are further down in the timeline.

You have two buttons and two shape buttons that pause the slide at 1.5secs, waiting for a reaction of the user. If you want the slide to continue to play, while the buttons remain visible and active, you'll have to extend the duration of the timeline of those buttons and make the pausing point happen much later (both can be done in the Timing Properties panel). Beware: you have another interactive object later on, another shape button, that pauses at about 11.5secs (the one with an effect applied to it).