With Hex-editing is actually quite simple
First download Dragon UnPACKer
Use Dragon UnPACKer to open the .ho file (BPXX.ho in my example)
you want to edit.
Then let Dragon UnPACKer search for the textures, choose the texture you want to edit.
Then drag and drop the texture onto your desktop and edit it as you like. (The Dino Texture in my example)
When you're done save it then, don't overwrite the original file!
Now open with a hex editor of your choice the two textures and your chosen .ho file which you want to edit.
Then copy the header of your original texture and search for this hex value in the .ho file (Note the Hex Offset| In my example 2EC8D40)
Once you have found the correct value, search for the lower half of the hex code.
When you have found this one too, write down the offset again. (In my example 2EF3877)
Next, right click on the hex code and select "Select Block" and add your offsets to it.
Press ok and the matching hex value should now be selected.
Now return to your edited texture, mark and copy the entire hex code.
When you've done that go back to the .ho file and paste the hex value into it.
If a message appears that contains so much that the hex value is extended, then it is the wrong texture you are currently editing.
Now everything should be ready! So save
file and see if it works.
If there are any problems or questions, just contact me!
Since you like the game just take a look at the prototype of it