As mentioned in today's review, the first series of Premium DNA's Earthworm Jim line is supplemented with a heads pack. Since one of the big draws of the game back in the day was the super-expressive art style, with Jim pulling all sorts of big, Looney Tunes-style poses and expressions, giving fans a bunch of alternate heads is great. And while they perhaps could have done them as pack-ins with the other figures, almost like a loose adaptation of a Build-A-Figure idea, making those heads a separate purchase for anyone who doesn't want all the other figures in the line is a friendly choice.
So, what new heads do we get? Let's take a look! Fortunately for us, the back of the box gives names for them, all taken from various voice lines in the game.
We'll begin with "Plasma!", the line said any time Jim picked up ammo for his gun. The faces don't really have any connection to their putative names - the expressions just cycled randomly in the game, it's not as if he always made this same expression while collecting ammo or anything. This is a happy head, though still a bit sinister, like he's laughing at someone's misfortune. The mouth is open wide, and the eyes are angry. This stands out nicely by being the only (open-mouthed) head without a bunch of giant teeth visible in one form or another, but that open mouth does mean the head wants to fold in on itself when you're trying to push the balljoint neck into its socket, so be careful.
Next we'll look at "Cheater!", which shouldn't have an exclamation point at the end: Jim does in fact say "cheater" when you put in a cheat code, but he says it with a flat affect, not excited. This head does fit that delivery a bit, being possibly best described as "disappointed" - the angle of his eyes and the set of his jaw do make him look like he's disappointed in you for taking shortcuts in life.
The most distinctive head in the set is "Ow!", because it's the only one that isn't worm-pink, instead representing one of Jim's pain states. We said there was a lot of Looney Tunes in the game, and this one shows us Jim when he's been burnt to a crisp, with the head looking like a burnt match. The head is thin and bent, and totally black save for a small spot of pink remaining at the tip. His eyes are large white orbs, with no remaining lids, so he looks like a cartoon character who had a stick of dynamite blow up in their face. It's fun!
"Groovy" is a weird one. The line is in there because Evil Dead/Army of Darkness was still a niche, underground thing to reference in 1994, and doing so would make you cool. The head has... a smile? It's sideways and looks positively unhinged. His eyes are fully open, and he's staring straight ahead. Is he supposed to look stoned? The tip of his head trails off to one side instead of falling behind him, but this is the worst one in the set. They should have named it "Oof!" Big oof.
The next head, "Oh yeah!", has a similarly crooked mouth, but the shape is smoother and the eyes are cooler. This head displays a lot more confidence than the last one, and that suits the character better. This is also the only head in the set with the tip pointing to the character's left instead of the back. None of the ones that come with the actual figure have that, either, so that's a bit neat.
And at last, we have "Wee doggie!", which for clarity's sake 
should be spelled "whee" - he's saying it like an excited cowboy, not like a Scotsman who saw a puppy. This is another angry head, though saying it that way gives it more credit than it actually deserves: this isn't really "another" angry head, it's the same angry head that came with the main figure, they've just painted the eyes looking forward instead of to the side. Are you kidding? All the things we could have gotten, all the things we didn't get, and one precious slot in this set it taken up by a head with repositioned pupils? This is like back when fans would get mad at the Four Horsemen for giving DCU Classics figures anything other than the most boring, straightforward face imaginable. "I'm angry that the head is looking to the side instead of staring blankly forward, cater to me!"
There are plenty of other heads they could still do in Series 2, if such a thing happens: give him Groucho glasses, or an afro, or any of the other things accessible through cheat codes. Do his helicopter head, that lets him fall more slowly. Give us something clever now, and then save the "we repainted the eyes" head for a second series.
This little box set includes one more piece, and it's really nifty. 
Since all these heads swap using the same balljoint, the set includes a small worm body, depicting Jim outside his super suit. It's a solid piece, with no articulation other than where a single head can be plugged in for display, but it's not something Premium DNA needed to include, and it's nice that it's here. The shape of it, and the weight of the heads, does unfortunately mean Jim will have to be perpetually looking up in order to remain balanced, which does make sense if you assume he's looking at other, full-sized characters, but is definitely worse for simple display options.
You know what we're really missing, though? 
Neither the full figure nor this set include Jim extended to his full length and being used as a whip! It's not the best attack in the games, but it's iconic, and it would have been a perfect accessory. You can kind of fake it with the pieces we got, but a real version would be preferable. Ah well, maybe if there's a Series 2.
