So I recently bought a Game Genie and I told SMWHacker (he was really interested to hack it), after about one hour of searching for the title screen (adresses are likely moved further), he decided to try to make the code to summon enemies in the game, it worked and I tryed (with his help) almost all values that are strange in HL, we flound 3 unused enemies and more floating unused stuff (that goes with water).
The first one was a FF3 like enemy trowing bombs at the character, it is half working. You must hit him once before the bombs are exploding and I think the bombs only have a very small hitbox that appear only for about 1 or 2 frames.
(The game is being played on a PAL NES, so the picture is streched and colors are a bit different)
The next one is a gunner, he looks like a spy or some guard, 2 palettes exists like the 1st one.
no picture at the moment
And now is the oddest enemy ever seen in a pirate game I think:
It's some kind of lizard that jumps around and spins at the same times (once it starts, it never stops). If it is summoned on the ground, you can see it walking then starting to spin and starting to jumps. It is almost finished, it can hit me but I can't. I think it is fully animated, maybe it was supposed to land after a while, or I don't know.
video comming later (I'll do one showing those 3 enemies and maybe 2 unused floating stuff)
Unrelated:
Another version of Tetris exists in South Korea !
http://cafe.naver.com/tekkenspecial - second article with [1] in red.