Because running programs in the Logisim circuit is incredibly slow, I decided to write an emulator for the DM-02.
The emulator features a (separate) text and video display, just like the Logisim circuit does. The only difference is that this video display supports 240x200 pixels instead of the puny 128x128 from Logisim.
Programs need to be assembled first before they can be loaded into the emulator to run. There is currently no option for editing programs from inside the emulator.
If you'd like to give it a go, the emulator is available online: https://dutchmaker.com/dm-02/emulator/
Code can be found in the GitHub repo.