Abridged Arena Array: Did you want to play on something other than "Minerva," "Neptune" or "Ultra-Earthshaker"? Too bad.
Might want to add "Nysa," "Vamped," "Logic," or anything from DKH these days.
Annoying Video Game Helper: With Descent 2 having more complex level designs than Descent 1, the addition of a Guide-Bot seemed like a good idea to help players not get lost. Unfortunately, the Guide-Bot is very easy to lose track of because of its fast flight speed and sudden, erratic movements. If the Guide-Bot comes back and sees you doing literally anything except actively following it, it will shoot flares at you to get your attention, sometimes damaging your shields in the process. Most players will leave the Guide-Bot in its prison cell and stick to using the Automap.
Descent 3 made some changes to the Guide-Bot to alleviate complaints fans had with its Descent 2 iteration. Its flight speed and movements are largely unchanged, but now it tries to avoid hitting you with a flare, and apologizes if it hits you by accident. The Guide-Bot being stored in the player's ship allows the player to deploy and recall the Guide-Bot at any time; you can just keep it docked and ignore it if you wanted to. The drawback is that now the Guide-Bot has collision physics, so it is possible for it to block your shots and ram your ship hard enough to cause Collision Damage...which it will if you recall it, because it enters its cargo bay by slamming into your ship at full speed.
The "Dragon" in the Proving Grounds of Descent 3 (which isn't acutally a dragon but a Giant Spider robot, it's name comes from it's dual flamethrowers) is pretty easy once you know the thing's weak point the back of the turret on the thing's cephalothorax. Also, the flamethrowers only shoot straight ahead and can't aim up, meaning unless you hover right in front of his face, they won't hit you at all.
Big-Lipped Alligator Moment: One room in Descent 3 level 14 has a huge monitor with a picture of real life kittens playing. This has nothing to do with the plot and is never brought up afterwords.
Complete Monster: Samuel Dravis is an executive with Post-Terran Minerals Corporation, or PTMC. In the second game, he refuses to pay Material Defender unless the latter does more work for him, and, at the end of the game, Dravis disables Material Defender's warp core. The third game reveals that Dravis was responsible for spreading the virus, and had the scientist who found it locked up in a private prison on trumped charges. The characters manage to rescue him and find a disk with damning evidence against Dravis, which they turn in to PTMC President Suzuki, only to find out that Dravis bombed the building and pinned it on the Red Acropolis team, which soon finds its headquarters under attack. While the building is partially evacuated, hundreds if not thousands of innocent people die in the process. The survivors spend most of the rest of the game on the lam, and even when they are able to clear their name and arrange a meeting with the Collective Earth Defense, Dravis sends a bunch of infected stormtrooper bots to destroy the ship, and when this doesn't work, he flees to hide in his lair on Venus.
Game-Breaker: Descent II added a few. The Omega Cannon is a homing weapon that blinds its targets. The Gauss Cannon is a massive upgrade to the Vulcan Cannon that deals tons of damage, uses the same ammo (whereas every other primary weapon draws from energy), has a very high rate of fire, and is hitscan in a game where most weapons have Painfully Slow Projectiles. No wonder the latter was Nerfed into the Vauss Cannon in Descent 3.
The Helix Cannon is a massive upgrade to the Spreadfire with greatly increased damage, rate of fire, and spread size. Though it consumes a lot of energy, it can mow down nearly any robot in seconds. In levels with a large amount of energy centers, the Helix is ridiculously powerful.
And then there's the Smart Mines, which take the merely-annoying Proximity Bombs and add in a crapton of homing projectiles, enough that one bomb can one-shot almost any Mook provided all the projectiles home in on the same target.
Gameplay Derailment: A small oversight in Secret Level 4 of Descent II completely changes the way the level plays. Normally, blowing up the reactor at the beginning gives you an extended countdown (125 to 375 seconds) to search for as many powerups as possible in the massive level, but since the initial grated door is only locked from your side, it can be opened from behind with a Guided Missile to skip blowing up the reactor completely.
Genius Bonus: The average teenager playing Descent II in the 1990s might have looked at the name of the final level, "Tycho Brahe", and dismissed it as being just as alien-sounding as the last seven levels they played. Students of astronomy or those well-versed in history, on the other hand, will recognize the name.
The Thief Bot in Descent II, one in each level.* Except for, strangely, the boss levels. This nasty bot would come sneaking up on an unsuspecting player — typically in the middle of a fight with other enemies. It would zap you with a special shot that made your view go all wonky, steal some powerups, and then zip off to the furthest corners of the level in an erratic evasion pattern. Incredibly fast and durable.
Internal Tactical Droids (which are Demonic Spiders on Insane difficulty), Sidearm Modulas (pesky little things that shoot flash missiles), ITSCs (like ITDs, but with missiles), Red Hornets, etc.
The Thief changes in Descent 3, in that it can cloak. As an upside, it can no longer screw your interface, but now comes with a weapon in the form of Seeker Mines.
Slightly less annoying is the "Old Scratch" robot in Descent 3, which tears off your weapons, but simply leaves them floating nearby. It's also much easier to kill.
Diamond Claws in Descent II. They can only attack at melee range, don't have too much health, and are easy to dodge in open areas... but there's so many of them. They are the game's favorite ambushers, often coming out of nowhere to start ripping through your shields. What's truly annoying about them though is the fact that if you shoot them with energy weapons (meaning 80% of all primary weapons), they fire homing plasma shots in response.
HRUMPHmm...
Basically, any enemy in this series that is not an outright Demonic Spider falls under this.
The little "Doink!" sound in multiplayer when someone dies. The little chirp the Guidebot makes can also be this, if you were lost at the time- which you most likely were.
The pickup sound. It can't be put into words.
The pounding "machine gun" sound of the Gauss Canon, which audibly reminds you just how badass the weapon is.
The dying shriek of the Thief Bot, especially if it had managed to steal some useful items from you.
Bosses in Descent make eerie ticking engine sound. They also teleport around the arena, sometimes teleporting right behind the player, causing the sound to suddenly become much louder. They also often shoot homing projectiles that make the player even more wanting to fly away.
Descent had Level 8. It's a loud level, with loud music, and high concentrations of loud enemies like Drillers and Secondary Lifters. Just a typical fast-pace run-and-gun level, right? Well, eventually you'll stumble across a quiet part of the level to catch your breath and CRUNCH! You've just met the quiet-as-a-mouse Advanced Lifter. That same run-and-gun level won't be the same when, knowing you have to dodge suicide rushes whilst under constant Vulcan fire, you have to be on the lookout for these quiet, sneaky bastards as well. And they appear just infrequently enough during the rest of the game to catch you off guard. Have fun!
They're red. The Mars levels are red. Do the math.
In Descent 3, the "Old Scratch" type robots have a dark gray paintjob that blends in extremely well with the game's frequently gloomy environments, and they're quite stealthy aside from a quiet, creepy noise they make occasionally. Hearing that noise in a dark cave tends to result in player panic and frantically looking around for said robot... which has a nasty tendency to then pop up right next to the player and scare the living daylights out of them.
Descent 2's Diamond Claw did this, too, except they didn't make that idle clicking noise. Just silence between the periodic HRUMPHmm... HRUMPHmm as it slowly approached the player. By the time you figure out where he i- CLANG!
In fact, almost every enemy robot (especially the old scratches, level 3 stingers, etc) can spell Nightmare Fuel for almost anyone playing Descent 3.
Oh, you might say, but most of these examples deal with robots that sneak up on you. Maybe if you turn off the music, you can hear them coming and they'll be less scary, right? Wrong. Those robots are still just as hard to locate, even without the soundtrack. You still don't know where they are or where they're coming from. Only now, you have a backdrop of near-total silence to enhance the fear factor. HRUMPHmm...
Mission 6 of Descent 3 takes place in a temple populated by "Martian Nomads" (these little robed humanoids that sometimes just walk on the ground, but have flying vehicles and attack you). The music is mostly drums and chanting (which seems way out of place in the Descent universe) and at the end you have to fight the Homunculus, while looks rather like a flying Rancor's head with a giant metal arm attached, and at one point it falls down and the Beagle comes to pick up the Phoenix (the whole reason for the mission), only for the Homunculus to suddenly start attacking again.
Mission 11 is also very creepy. It takes place on an old abandoned factory on Titan that's for some reason still used to hold a pilot captive (who you are going to rescue). The background music is a creepy, distorted version of the level 7 theme, and for some reason the Beagle maintains radio silence for the entire mission, making you feel even more isolated. And when you finally do find and free the pilot you find out it was a trap and that Dravis's minions are waiting at the exit to catch you in a tractor beam and put you in the Proving Grounds.
Nintendo Hard: The first game became rather hard after the initial seven levels (which made up the shareware version), although of course it has several Difficulty Levels, as well as mid-level saving. The second game, compared to the first on the same Difficulty Levels, was easier on Trainee, but a bit harder on the higher levels. The third game was generally easier except for some incredibly obtuse puzzles and gimmick sections loaded with Fake Difficulty.
Polished Port: The Macintosh port of the original Descent allows the player to play at a doubled 640×480 pixel resolution or 320×240 pixel resolution which matches the MS-DOS version resolution. Several but not all of the tracks from the MS-DOS version were remastered into CD Red Book audio since Macintoshes only have software-driven sampling audio systems, CD audio players, and no hardware synthesizers.
That One Boss - Many of the bosses, due to being armed with the most powerful weapons in the game on top of being accompanied by a small army of Mooks, and some of whom are Mook Makers to boot.
In Descent, the Super Hulk was tough enough, until you learned that its shots don't track well when circling around the center pillar, and that it's possible to move freely in all directions without turning. Regardless, both bosses in that game tend to land a One-Hit Kill without a direct hit.
The available powerups made the Super Hulk in Level 7 a lot harder than the End Hulk in the last level, though. By the time you face the Super Hulk, your strongest weapons are the Spreadfire Cannon and Homing Missiles, but you get Smart Missiles and Mega Missiles (which the respective bosses use) within the next few levels. You also have a lot more available invulnerability and cloaking powerups in the final battle, instead of one each and a few shield boosts in the Super Hulk battle... and did we mention you're locked in the boss room upon entry in Level 7, but in the final level, you're not?
The Ice Boss from Descent II takes the cake for pure frustration. He fires homing Flash missles (which blind you) and an Omega Cannon (the strongest primary weapon in the game) which also blinds you. Meaning that unless you stay up in the passageway leading into the Boss Room (which protects you from most of its attacks), you'll likely be flying completely blind for the entire battle. It's also immune to energy weapons, meaning that the only two primary weapons that even affect him are the Vulcan and Gauss cannons. Hope you've been conserving ammo...
The Homunculus in the third game: it's ridiculously fast for its size, it can rip the player apart in seconds if it gets close, it can spam powerful homing projectiles from afar, it's accompanied by a whole damn swarm of other robots (including the aforementioned Old Scratch type), and there's no place to hide in its chamber. Oh, and it's just a little over the third of the game in, when the player doesn't even have any powerful weapons.
Sequel Difficulty Spike: Robots in II tended to be either faster, more evasive or able to fire a lot more rounds at a time than their closest counterparts in the first game, and could also carry two kinds of weapons rather than just one.
Enemy AI was also improved a lot in II, averting Hero-Tracking Failure which I played straight, and adding several new settings to assign to various Mooks in the mines. New options included "Get Behind," "Follow" (opening doors and rushing between rooms) and "Snipe" (hit-and-run tactics and a berserk firing rate). This also means making robots look like they're adapting over the course of the game as for example, the Smelter normally fires only three or five Phoenix shots at a time in Normal mode, but the last few levels with it have many set to Snipe mode.
That One Level - Level 6, Level 11, Level 19 and Level 26 tend to be this in the first game. All are chock full of Demonic Spiders and none have all that much hiding space— for example, Level 19's circular design means you could be attacked from any direction, and in Level 26, you're forced to retrace a narrow set of tunnels whose crossroads trigger the only Fusion Hulk Mook Maker in the game... and they can shoot at you from outside the tunnel. There are token cloaking devices or invulnerability globes, but predictably in hard-to-reach places.
They Changed It, Now It Sucks! - Descent 3's addition of gravity and change from flight-sim style aiming to FPS style aiming prompted revolts from fans of the first 2 games. Some gamers also cried this because most of the weapons in Descent 3 were either useless or much weaker than the ones in Descent and Descent II.
Players who preferred to play with joysticks didn't like that players who used their mouse and keyboard to control (read: almost everyone who played a First-Person Shooter) were a lot better at aiming and rapidly switching targets. The default configuration for a Descent 3 multiplayer server did not allow people using mouse and keyboard to play.
Descent 3 defaults the turning system to "Flight Sim", not "Mouselook", so there's some latency to the turning.
What about the increased turn speeds that Spacetec SpaceOrb 360 users had access to in the first two games?
The DXX Rebirth project mostly aims to recreate the feel of the original 2 games authentically, with some quality-of-life improvement options. One of which is the option to enable full speed Mouselook if players want (which can be disabled by the host in multiplayer matches).
to skip blowing up the reactor completely.