ok so, the first thing to do is understand how the ship moves. Movement on your three axes is independent - when you accelerate forward, you move forward at the same velocity regardless of whether you are also strafing, and the same goes for the other axes. The vectors are simply added together. As a result, the fastest way to move in one direction is not to face that direction and accelerate. It's to face at an angle away from that direction, and simultaneously accelerate and strafe on both axes. People call this "trichording" for some reason. This is a good time to mention that you should bind dedicated strafing keys. The strafe toggle is convenient, but being able to strafe and turn at the same time is really important; it's the only way to circle a target and keep facing it, for example. Lots of people just use joysticks or the mouse to turn, but keyboard-only controls are fine so long as the keyboard supports enough simultaneous keys (it's what I use!). Strafing/turning together is 8 keys, so it can be tricky to arrange. I use the cursor keys plus home,del,end,pgdn, but that's because my keyboard has home,del,end,pgdn placed abnormally low so that I can reach all of them easily with one hand. I think most people use one hand for strafing and one for turning instead, which is undoubtedly easier but I don't like it because then I don't have a hand free for switching weapons. Oh, and get used to toggling the rear view a lot.
the next thing is to know the weapons:
level 4 quad lasers have the highest dps, best energy efficiency, and smallest hitbox radius (= best for fitting around corners), but are also the slowest traveling and thus hardest to hit with
vulcan cannon has the worst dps outside of low level lasers and a speadfire cannon with only 1/3 of shots hitting, but it is the fastest traveling and has the fastest fire rate. it's not actually better for stun-locking robots than plasma cannon or lasers!
spreadfire technically has the second highest dps if all 3 shots hit, but that's impossible except at very close range, and it has the lowest dps if only one shot hits (even lower than a plasma cannon with only one shot hitting). because of this it's mainly good in multiplayer; if you want something faster in single player, plasma cannon is better unless you really need to conserve energy
plasma cannon is completely average in dps, speed, and hitbox size. it actually has the worst energy efficiency, but it has speed, and it has a more practical firing pattern than the spreadfire cannon, especially in single player, so it's still good
fusion cannon has really bad dps (almost as bad as vulcan cannon), energy efficiency is almost as bad as plasma cannon, and the firing rate is obviously the worst too. however, the projectiles travel really fast and have the biggest hitboxes by an enormous margin, which makes it amazing in a lot of circumstances both in single and multiplayer. fusion cannon projectiles also have the peculiar property of penetrating through robots and ships they hit, something nothing else in the game does, which is nice in single player.
concussion missiles are boring
homing missiles are mostly intuitive but have two surprising properties: first, their damage is actually higher than concussion missiles' (27 vs 20). second, in the original Descent (source ports fix this), their turning speed is framerate-dependent; the higher your framerate, the faster they turn. (framerates above 30 also speed everything else up, and insanely low framerates also slow everything else down, but neither of these happen in practice in any significant situation, unless you're running dosbox on a heavily overclocked i7 or something.) to avoid homing missiles that have locked onto you, you need to either place yourself outside of their turning radius, block their "line of sight" with a wall, pick up a cloaking device, or just make them run into a wall (ducking behind a corner is the easiest way to do that). to place yourself outside a homing missile's turning radius, accelerate directly towards it and veer sideways at the last moment so that it can't turn fast enough to follow you. you may need to trichord. note: at 30 fps, this is HARD.
proximity bombs basically suck but you can try putting them around corners and tricking people into flying into them. in single player, putting them in matcens that you are about to trigger, or in front of doors that are about to open and release robots, is occasionally useful
smart missile blobs work the same as homing missiles except they're slower, no problem to dodge if you're ready for them. amazing in single player
mega missiles also work the same as homing missiles
this is all the game-specific information you need for multiplayer. to be good at single player on high difficulties (ace and insane), you'll want to have some combination of the following:
1. knowledge of how the AI works
2. advance knowledge of the levels' layouts and object placements (probably by opening them in an editor)
3. good technical skill to dodge attacks and quickly destroy robots
1 and 3 are a lot more interesting than 2, and apply to all levels instead of just one, so those are the ones I'll cover.
to understand why the AI behaves the way it does, it's good to first know how the computer sees levels. All levels in Descent are made up of many 3D blocks. Each block has 8 points and forms a convex six-sided figure.* Each side can be either shared between two blocks (in which case it's empty space) or not (in which case it's a wall). To clarify, space INSIDE the blocks is empty space. Space OUTSIDE the blocks is solid wall. Here are two screenshots:
http://sdldevil.sourceforge.net/sdldevil4.pnghttp://sdldevil.sourceforge.net/sdldevil5.png*Exception: In rare cases, the 8 points are arranged such that the six-sided figure is not convex. This means that one of the sides would have to be twisted. Instead of doing that, which would cause many problems, the game simply splits that side into two triangles that approximate that twist. This doesn't really ever matter for gameplay, but the texture alignment code doesn't like it, so it looks weird if you view it from an extreme angle.
Why does this matter for gameplay? There are two ways. First, each side of each block has a specific ordinal number from 0 to 5. The adjacent sides of two blocks are only considered to form a continuous wall if their ordinal numbers match. If they mismatch, and there is a sufficiently sharp OUTSIDE corner between them, it is possible for the ship and robots to become stuck on the corner. The official levels are VERY good at avoiding this, but it slips through sometimes. The second way is how the AI pathing works. When a robot wants to move, it picks a path to move along, and the arrangement of the blocks influences that path - two arrangements of blocks that create the exact same 3D space could still result in robots taking different paths between them. In general, robots like to go to the center of blocks, especially medium lifters, advanced lifters, and mine layers.
Now, let's talk about robot awareness. The main ways to make a robot aware of you are for it to see you, for it to hear you, and for you to hit it with something. All robots have an "eye" on the front of their bodies, and all robots have a field of vision (I believe it is just a cone). This field of vision varies for each type of robot, and it becomes both wider and longer with higher difficulty levels. Robots cannot see through solid walls or closed doors. Robots can pitch, yaw and roll just like you, but they generally don't roll significantly except to poke their guns around corners or to turn to face you slightly faster. Exception: spiders roll all the time for no apparent reason.
Robots in Descent have 6 behaviour modes that are set by the level and do not change:
Normal: Can be seen as the "default" behaviour, both because of its name, and because it's the behaviour for robots that come from a matcen. Will move to pursue you, but doesn't patrol around like Station robots.
Still: The robot is very reluctant to move, except to dodge attacks and to momentarily peek around a corner. I don't think it will ever chase you. Used a LOT on medium/cloaked/red/fusion hulks.
Hides behind: This behaviour is never used in Descent 1.
Drop Bombs: As soon as the robot becomes aware, it starts running away from you and laying mines. Can be applied to any robot but you'll only see it on retextured Class 1 Drones and Gophers.
Snipe: This behaviour is never used in Descent 1.
Station: This is the scariest behaviour. As soon as the robot becomes aware - which can happen when you're very far away - it starts patrolling around its "station", which is somehow determined by block and door layout, and often consists of most of the level. If it sees you once, it will pursue you *relentlessly*, and at a variable speed. A pursuing robot will often hide behind a corner for several seconds, then jump out suddenly and attack. Class 1 Drillers are recklessly aggressive, and will barely wait at all before leaping around the corner; they also leap faster and further than other robots. Medium Hulks take it a step further: if you're around a corner, sometimes instead of going around the corner themselves, they'll lean and poke one of their guns around the corner and fire. (All robots with multiple guns are able to just use a single gun in this way if they're caught in a situation where only one gun has line of fire to you, but Medium Hulks seem to be the only ones that deliberately set this situation up). Combined with the fact that they're one of the quietest robots, and are happy to wait a *ridiculously* long time before actually going around the corner, they're uniquely dangerous with this behaviour mode.
Now, a note about difficulty scaling. Every time you increase the difficulty level by 1 unit (e.g. Rookie -> Hotshot), the following things happen:
- Shield and energy powerups give 3 fewer shield/energy points.
- All robots become faster in all respects. They move faster, dodge faster, and shoot faster.
- All robots get wider fields of vision.
- All robots fire more projectiles per burst.
- All robots dodge more often (except for bosses, which never dodge).
- All robot weapons travel faster, accelerate faster (if applicable) and do higher damage. However, some robots fire the PLAYER versions of weapons instead. These robots are Class 1 Drillers, Cloaked Drillers, Fusion Hulks, and IIRC both bosses. These robots' projectiles don't change with difficulty level. However, the robots will still fire more often and fire more projectiles per burst. This is why Class 1 Drillers do disproportionately high damage on low difficulties. Note that the splash radii of concussion and homing missiles increases with their damage.
- The skill bonus for beating a level increases, I forget how.
This is my tier list of robot threats in the original game's levels for Ace and Insane difficulties.
F tier, it's rare for me to take damage from these at all, or even have to pay attention to them when fighting other robots:
- Class 2 Drones. Really slow, weak projectiles, the robot itself isn't very fast, and it can't even dodge well. Free shield powerups.
- Small Hulks. Same weak weapons as Class 2 Drones, although it takes longer to kill since it has more HP and can actually dodge. Also quieter, but you can just react to the sound of their projectiles instead (if they ever sneak up on you in the first place, which is unlikely to happen). Free shield powerups.
- Medium Lifters. They have to get into melee range to do any damage and they're not good at doing that. Free shield powerups.
C tier, sometimes threatening but generally not:
- Class 1 Drones. Huge damage output on Insane, but their projectiles are still not THAT fast, they aren't sneaky, and they are pretty easy to kill.
- Spiders. Less offensive power than Class 1 Drones, and a lot less agile too, but requires some commitment to kill safely (the spawn can be bad if you don't kill them immediately after the spider).
- Spider spawn. These try to fly REALLY close to you, so they can be a problem, but they die very fast.
- PTMC Defense Prototype. Like fighting a bunch of Small Hulks at once except you get no shield powerups.
- Class 2 Platforms. Really good at using corners, but that's about it.
- Gophers. Just annoying.
B tier, need constant attention to avoid damage but are easy on their own:
- Cloaked Lifters. Too loud to sneak up on you, but since they're cloaked they require a lot of attention to avoid and kill.
- Advanced Lifters. Like medium lifters, they have to get close, but unlike medium lifters they're the fastest robot in the game. To run away from one on Insane you have to exploit block layouts. So if you don't kill them right away it's pretty bad. Contrary to a common myth, these aren't silent, or even especially quiet.
- Secondary Lifters. Weak weapons, but they try to fly extremely close to you, which is very bad. And when set to Station, they're the most aggressive robot in the game, you pretty much can't even get them to wait around corners; if you let one see you, you have to commit to killing it, like Advanced Lifters, but unlike those, secondary lifters are ranged!
- Supervisors. No weapons, but they alert other robots from far away, which is a big problem with Station robots (level 8 is a great example).
- Heavy Drillers. Huge damage output with a fast weapon, but it's still pretty easy to dodge, and they don't do anything tricky. They have a similar level of aggression to Class 1 Drillers, but move extremely slow compared to them, and don't do the same exaggerated leap around corners that Class 1 Drillers do.
- Fusion Hulks. Yeah, they can 1-shot you, but they're the worst robot in the game at moving around - even set to Station, they barely move, and they pretty much don't dodge at all. Additionally, they don't account for the huge hitboxes on the fusion cannon when they fire, which gives them the dubious distinction of being the only robot in the game that can't successfully fire around a corner.
S tier, unless I know exactly where it is ahead of time, I'm probably going to take significant damage:
- Medium Hulks. I mentioned their scary AI earlier, they're very quiet, and they put out tons of damage.
- Red Hulks. These are way worse than Medium Hulks that you know the position of, but since the don't move nearly as much (aside from dodging better), a Red Hulk is way less likely to take you by surprise. They require more care than any other robot in the game to kill, but again, they aren't as good at sneaking up, so I don't think they're more dangerous than Medium Hulks.
- Class 1 Drillers. Fastest projectile in the game, and the only one that is pretty much undodgeable. (it's not instant, but you'll still get hit at long range because they have a wide spread!) And they move a LOT, and leap around corners instead of peeking around them, so reacting in time to kill them before taking damage is practically impossible. These are the sole reason that everyone keeps homing missiles selected by default.
- Cloaked Hulks. These move very little, but their firing rate and HP are both significantly higher than Medium Hulks', and, of course, they're cloaked. Unlike other cloaked enemies, they don't drop cloaking devices, which is rather insulting.
- Cloaked Drillers. These move a little more than Cloaked Hulks, but less than regular Class 1 Drillers. Having the same weapon and small frame makes them pretty scary, but they aren't aggressive, so they don't typically do THAT much damage.
SS tier, these routinely kill me on their own:
- Green Class 2 Platforms. Fucking god, missile platforms. Doesn't matter if you're at 150 shields, get hit by one missile on Insane and the hitstun makes you get hit by the rest and you die. And the missiles are fast and have huge splash radii. Not only are they the game's touch of death enemy, but unlike red hulks and fusion hulks, they actually move around. They move around a lot. No other robot is as dangerous in close quarters, and close quarters describes 99% of the terrain in this game.
How to beat the first boss: Save the invulnerability charge outside its room. Use it, along with homing missiles, to kill the drillers and ideally the Red Hulks in the boss room. Get the cloaking device at the bottom of the pillar before the invulnerability runs out, using it to clean up any remaining drillers/hulks. Once you've done that, start attacking the boss, hugging the pillar. Whenever you have smart missile blobs following you, fly along the wall of the pillar; they'll get caught on the corners. Tip: You can prop open the one-way door to the boss room by putting a proximity bomb in the doorway, if you want to try to use multiple cloaking/invulnerability charges from outside the boss room. Each bomb will only last 30 seconds, but that's all you need anyway.
How to beat the second boss: There are 4 invulnerability charges in obvious nearby rooms; just use those. Directly opposite the entrance of the boss room is another secret room with a bunch of extra weapons and 6 cloaked lifters (extra cloaking devices) if that's not enough.
Sunday, 10th January 2016, 15:31 
