Technos Japan's prototype for Double Dragon II: The Revenge was one of the more unique ones seen. It came inside a Disk System RAM adaptor.

Double Dragon II: The Revenge inside HVC-023.

Should we give that that phone number a call?

Things to note:

   - HVC-TK22EPROM-01 on inner board matches outer label.
   - TECHNOS JAPAN Labeled Program & Charachter EPROMS
   - Sample Title Screen Version C. 1989 Technos Japan Corp.
   - You get UNLIMITED CONTINUES with this prototype
   - Between continues there is the option to change difficulty settings
    (and swtich between the 1-player and 2-players modes)
   - Screen after the start screen says "Double Dragon" without the "II".
   - The ceiling spikes don't injure you when you jump into them.
   - You can do jumping knee rams under spikes and your life meter

     won't go down.

Double Dragon II: The Revenge board.

More differences:

   - Helicopter doesn't shoot at you on easy.
   - The fortress tank doesn't vent steam at you.
   - Antagonists become progressively tougher.
   - No disappearing platforms or falling fire on easy, likewise with

     medium. Difficult has fast disappearing platforms.
   - The wheels move faster on difficult than medium. No spikes fly up in

     the wheel room on easy.

The start screen reads "Sample Version".

This select screen titles the game without the "II".

Infinite continues means nothing can stop you.

Safe at last, as expected.