The first few enemies have painfully slow lasers that hit for like 3 damage each, along with a rocket-shooting mook that deals 12 damage on a direct hit. Those guys are pretty easy to deal with, since you can fly twice as fast as their shots. Then there's a tougher edition of that rocket-shooter that can take a shitload of damage and shoots HOMING rockets, which are impossible to outrun and fairly difficult to dodge around (so you better hope there's a corner nearby). Oh, and did i mention all those rockets have an unreasonably large splash radius? Because they do. It's not impossible to survive though, since in open areas, you can zip past the rockets so fast that they can't turn quickly enough, making them lose track of you.

But then, THEN comes a foe with a hitscan(!!!) vulcan cannon, which will typically tag you for 15-20 damage if it catches you off guard, which it does 90% of the time, typically when you open a door or round a corner. In open areas, it IS possible to dodge by merit of them having a slow turning rate, but if you don't move constantly, it's going to hurt. Later on, these come in a cloaked and slightly tougher variant, which hit just as hard. The first encounter with these is a large room with approximately 6-8 of these foes AT ONCE, so basically you die half a second after entering. This room alone killed me 5 times. The first boss killed me once or twice, while the final boss didn't kill me at all. What the ♥♥♥♥, Parallax?

Most other foes are reasonably fair, except for two additional ones: A standard mook that shoots bursts of 3 dumbfire rockets with little delay between bursts (which is a lot of splash damage), which in and of itself isn't THAT bad, but if you round a corner and see this guy, you WILL eat 3 rockets, which takes off a godawful amount of shield (and in the later levels, you RARELY have full shield).

Finally, there's a big purple bugger that shoots fast purple energy blasts at you, in straight lines. Not homing makes it easy, you say? Well sure, if you discount the shots' gigantic hitbox, high speed and INSANE power. Insane as in "takes off 80 shields in one shot". I'm not even kidding, they do 80 damage on the second easiest difficulty. Better have your dodging skills maxed out by then!

So let me sum up the damage per shot you can expect in Descent over the course of the game:
3 -> 3x2 -> 12 -> 3x7 (hitscan) -> 6x2 -> 12x3 -> 80