Presentation for bad guys is just as important as how tough they are. For instance, comparing Boltgun with Dark Forces, both of them are sprite-based FPS shooters with 3D backgrounds, but the latter did a better job building up the Dark Troopers than the former did with the Black Legion.
In Dark Forces, you see Vader and his new buddy, General Rom Mohc, sic the Dark Troopers onto a rebel-held world, and within moments of them landing on the planet, a battle starts........then stops. Later, Mon Mothma briefs you on what happened; a shielded rebel base inside a city just got annihilated within minutes by Dark Troopers. You encounter your first Dark Trooper at the mid-point of the game as the boss of a level, and they get stronger as the game moves on. The game uses the Dark Troopers sparingly, and as a result, they retain their special quality; they're not only damage sponges, but they can blow you away easily, as well. Imagine the Brutes from Halo 2, except they've got no headshot weaknesses, they've got weapons that can insta-kill you, and they've got jetpacks. Which makes sense why there's not even 20 of them in the game.
Meanwhile, in Boltgun, the Black Legion just happens to be on Graia. No buildup, nada. Just some Inquisitor telling you that there might be Chaos forces down there, and a vision of some Chaos sorcerer holding the planet in his grasp. Then come the second level, you meet your first Black Legion Space Marines without much fanfare or fuss; and you start killing them like they're just cultist mooks with extra health. So it doesn't really feel that special when you kill your first Black Legion Space Marine, and by the end, you're just killing them left and right, like they're mooks with extra padding. The only real threat among them are the ones who rush you and can revive themselves. Outside of them, killing the rest of the Black Legion, including their Terminator Marines, is about as mundane as stomping on a Goomba in Super Mario Bros., so long as you have enough ammo.
For example, you can use plasma guns against both the Dark Troopers and the Black Legion. But with the latter, killing them with a plasma gun is easy so long as you have enough ammo, and even their champions who rush you can be easily dispatched with plasma fire. Whereas with the Dark Troopers, it's advisable NOT to use the plasma cannon against the more primitive "shield and sword" Dark Troopers, because they can deflect your plasma bolts back at you, whereas with the second version of the Dark Troopers, they zip around the battlefield while firing their plasma cannons and missiles at you, making the fight much harder since you have to run really fast to avoid their plasma fire while you're trying to hit them with yours, and it'll take a considerable amount of plasma cannon fire to bring them down.
Both games are great, both games have a decent challenge curve and enough resources for you to win, but Dark Forces has better presentation for the Dark Troopers, as opposed to Boltgun just shoving the Black Legion in your face without much explanation as to why they're there or what they're after. The end result is that the player remembers the Dark Troopers as a genuine threat, whereas the Black Legion in Boltgun are just there to be your punching bags.
