Today I'm putting the inventory system on hold in favor of enhancing the map editor. This will be in favor of an easier to use interface as well as the ability to use more than one tileset for different maps.
Also I've often considered making a special map editor that other people could use to make custom Spike's Quest levels with a level player emulator. This could be used to make some challenging levels of your own to share with others. Kind of like those Mario Bros level editors that we often see floating around the internet from time to time. Not sure if such an project would be ready for the next test demo, but we shall see!
Another note, I've been considering redoing Spike's sprite set making it look better and whatnot. its a huge 'maybe' though so dont go expecting it :P