Lost Earthworm Jim Cartoon Pilot

Wow, I've been an EWJ fan for a while and I've actually never seen this promo; very interesting find! It reminds me a bit of the Mike Dietz demo reel animation from the game that he had on his website. The animation and character models definitely appear to be different from the actual show. Like you said, all the character designs seem to be more closely based on the actual game designs, even with Princess WHN not having chest armor and Peter Puppy looking more quadruped and purple-ish. I want to say maybe Fifi the junkyard dog is next to Evil the cat as well? Hard to tell it's so pixelated.
It's really cool that they were possibly considering Doc Duodenum and Major Mucus in the actual show too, I always wondered about them possibly showing up since Major Mucus was feature in the toy line.

The original show was 1995-1996 so if this promo was in '95 my guess is it was actually some sort of pitch/promo material made before the 1st season was even put into production and they simply re-used it to promote the show coming to Kids WB. It's hard to describe but the animation has a certain quality to it that makes me think it wasn't made as part of an entire episode. Almost like it's too zany and erratic? It's definitely not bad (I like this sort of animation!), but it's kind of like the type you'd see in cereal commercials and stuff where a lot is happening and the animation is wacky, since a commercial only has a short amount of time to get whatever it's trying to show across. I wish I knew how to word it better haha.
 
To be honest I think that this was created purely as a one-off animated pitch to see if studios were interested in funding a full fledged animated TV show, and it doesn't include any footage cherry-picked from a lost pilot. Mind you I would LOVE to be proven wrong and see more Jim and company animated in this zanier style. I'm not saying there isn't a pilot episode lost to the public, possibly even containing these same designs, but I just don't think this particular promo contains footage from a lost pilot episode.

But either way I really enjoy seeing this, thank you for posting it! I'd love to see this promo in better quality so all the different character designs and animation could be seen much clearer.