Jazz Jackrabbit is illegal, because jazz music was first. Bow down to jazz musicians!
Why would such a geek like Devan have a castle? I know he's stupid, but he also loves technology. On your screenshot I can see a knight. Maybe it would be some kind of a future castle, where knights are robots and it is surrounded not by water, but acid (). There is a lot what can be designed, but as I believe, not much possible. But at least try, 'cause Devan surely doesn't like wooden doors and stone walls.