Thanks for the comments guys!
Myself and Nuntar were playing this yesterday and came up with two challenges that ended up being quite fun to play and changed things sufficiently enough that I've implemented them as extra scorepoints. Sadly, achieving both at the same time appears to be impossible, best I can do leaves me around 800 HP short, which is quite a lot.
This version is attached to the opening post.
The ending text and some NPC text has changed, to drop hints as to what the challenges are. The ending text is now dynamic, changing with one of the challenges. Note that due to the way RPG saves rooms, you'll be best to start a new game if you want to try these challenges, that will avoid any scripts only half-working.
There have been no gameplay related changes made, although sword and shields no longer leave behind a slot or the previous weapon. I figured it was best to not change anything and leave the speed architecture to stand on its own, but it still turned out well regardless so not a problem.
If you don't want to go to the barely minimal effort of figuring out the challenges for yourself, here they are:
Click here to view the secret text
×* Defeat the Goblin King without the goblin-biter (not too hard)
* Defeat the Goblin King without the shield (much more difficult)
I can't imagine anyone will find any issues and unless there's a game-breaking bug I don't plan to make any gameplay changes, so I'll submit this to the HAs in a few days.