Object is to clear each board. To clear the board, do one of the following:
- kill all the monsters
- knock out all the cherry blocks
- spell EXTRA
- pick up a diamond
To open the door at the top of the screen, knock out the three keys. When the door opens, grab the shield and all the monsters will turn into EXTRA letters. Diamonds randomly appear after knocking blocks out. You can push the angled ladders left and right. On some paths you'll see two skull blocks. Knocking them both out will knock out all the blocks in between. Use that to your advantage when being followed by several monsters.
I'd keep it Mr. Do!s Castle and wait for a Kangaroo kit to convert it back, then put the MDC kit into a more generic cabinet.