My film didn't fully develop

It looks like your film was developed just fine. What you're seeing is fogging by an unwanted light source. The sprocket hole 'ghosts' are quite indicative of this. It seems the film was fogged when it was rolled up, as light passed through the sprocket holes and hit the film behind it.

Carefully go through the steps and see where the fogging may have occurred. Perhaps you opened the film door as the roll was still outside of the canister, or some moment during loading/developing the film was struck by light. Based on the pictures I do not believe the camera to be at fault.

Looks to me like some sort of light leak, given that you've had success with some frames on the roll and the film code is clear and legible on those frames.

The first pic is simple what happens when you don't load your film into the camera in complete darkness, and light exposes the film between the leader and the first frame. This is to be expected; some people even find this appealing.

The latter pictures seem to show the faintest hint of some frames which would imply that the camera is still working, but seems like the film has been exposed to light at some point before or after this. There are several ways this could happen:

• Camera: How old is the camera? What type of camera is it? Are the lightseals intact? Did the film door open while there was film in the camera? (I've had this happen on an old Olympus Trip 35 and have since used duct tape to make sure it doesn't happen again).
• Developing: Loading film into a tank requires total darkness. Even a darkened room (rather than a dark room) could still have some light coming in from somewhere, even at night. If you think this is the case, you could invest in a changing bag, or carry out the loading process under a thick blanket, in your darkened room, to see if the problem persists.

I've shot and developed a fair bit of HP5 in my time and I've never had results like this from developing, but I suppose I can't rule out your chemistry as part of the problem, since I've only ever used Ilford DD-X or Rodinal.

A couple of further tips which could be beneficial:

• Don't shoot anything you can't afford to lose while you're learning how to develop;
• From the looks of it, the film could use a couple more minutes in the fixer bath. Underfixed film runs the risk of fading over time (more than a fully fixed negative);
• Don't give up :)