Yes there is several ways this can be done.

1) You can set a slide to Hidden and it will not display during slide show mode but is still visible in your presentation. To check this have a look at the slides which did not display, where the slide is numbered in the Slides pane does the slide number have a strike through in it? If yes then it has been set as Hidden. To undo just right mouse click on the slide and click Hide Slide to undo this setting.

2) You can setup custom slide shows which only display certain slides during slide show mode. Go to the Slide Show tab and click the Set Up Slide Show button. Ensure in the Show slides section that the option is set to All so that all slides are displayed.

Let me know how you go.