Had kind of a breakthrough, it's looking something like working, still lots of bugs and ugly static blocks, but it's better.
Pretty much working, small bug in blocks stopping when they shouldn't. Extracted colours into class to allow drawing them on settled blocks. No score or line clearing yet.
Finally added all the shapes and coloured them properly. Got faster falling working nicely when you press the down arrow.
Game virtually entirely working. Bugs to fix with the line clearing algorithm and the moving from far right. Added incremental difficulty. Need to add scoring to side panel.
Added all necessary Javadoc. Previous bugs still exist.