Awesome Music: The music that plays during the introduction cutscene. Sadly, currently there isn't a SFX-free version of this song available.
Cult Classic: The Rock Raiders toy line and PC game may not be particularly well-known, but it has a strongly devoted fanbase. The modding possibilities for the PC game has only increased the appeal, as an entire online community has been built around mods for the game.
Demonic Spiders: Slimy Slugs take inordinate amount of shots from the Laser Gun to kill, and will only be warded away by the recommended weapon, the Sonic Blaster (of course, this doesn't really work and you have to resort to Pusher Beams). They also have an energy-draining attack that makes energy crystals useless.
Game-Breaker: The Chrome Crusher. For that matter, The Tunnel Scout to all water vehicles. When edited in, the Tunnel Transport even more. In fact, many vehicles are useless.
The handheld Laser Beams pretty much nullify the threat of Rock Monsters and Ice Monsters.
Goddamn Bats: The bats and the spiders, which do nothing except scare or trip the Rock Raiders, slowing them down or permanently cancelling their orders.
Good Bad Bugs: Rock Raiders can walk diagonally between squares even as long as the destination is walkable terrain, which allows Solid Rock and sea corners to be traversed. However, the pathing engine will also make the Rock Raiders walk on lava if an acute angle is walkable. Additionally, if a rock raider is interrupted when carrying an electrified fence to place it on a square, and he is interrupted (such as by the Spiders) he will drop it, and an electrified fence can never be built in that square anymore, and often the fence will never be picked up. As when extra ore is placed on a building and not picked up until your air supply is gone.
Funny Moments: There's a very dramatic sequence in one of the pre-mission cutscenes where a Rock Monster emerges from a wall and marches menacingly towards the Rock Raiders' Chrome Crusher. The Rock Raiders flee before it, but Docs is unable to escape, and cowers in fear as the Rock Monster looms over him. The Rock Monster ignores Docs entirely, takes a single Energy Crystal from the Chrome Crusher, and walks away while cradling the crystal in its arms like a baby.
Back to Basics is an evil pit of Slimy Slugs. Not only that, but your air supply runs out unnaturally fast (which makes sense, since you are so far underground) which means having a support station is absolutely paramount. If the Slimy Slugs get to it (and at some point, their bound to) and drain all of its energy, you have perhaps 2 minutes max to get power back to it, or its game over. Speaking of power, actually finding energy crystals is very difficult, as the level is designed so that energy crystals are significantly more difficult to find, meaning you have to spread your resources thin to find them, which leaves your base relatively lacking in manpower to defend it. And you'll need that power to fend off rock monsters that frequently attack it as well. Unfortunately, Back to Basics must be won to unlock the final mission. What's even worse is that the AI has a tendency of glitching out on this level, where if you break too many walls, your units may suddenly cease to pick up any energy crystals lying around, no matter what you do.
Don't Panic. First you spend several minutes running from lava monsters and a lava river, then you spend what little Oxygen you have left either collecting Energy Crystals or quickly building a base, and then collecting Energy Crystals. There is a secret path you can drill through which will take you directly to the area with the Energy Crystals, if you can find it.
Lake of Fire. In most levels where erosion is a hazard, you are given enough cavern space that, as long as you maintain a strong Power Path dam to block the lava lake, you should not have to worry too much. In Lake of Fire, most of the cavern is filled with lava, with only very thin land bridges leading from one rock formation to another. If you spend too much time building Power Paths, the land bridges in deeper parts of the cavern will have eroded away by the time you get there, and before you know it, the precious Energy Crystals contained within those rock formations are lost, making the level Unwinnable by Mistake. On the other hand, if you don't build any Power Paths, the land bridges closer to your base will erode away much faster, and the land bridges far from your base are going to erode away anyway. And did I mention that the whole level leaves you Almost Out of Oxygen, making a Support Station a necessary priority on top of everything else?
Tier-Induced Scrappy: Most of the vehicles are considered useless by the average Rock Raider player, but special mention goes to the Hover Scout, which cannot travel over water or lava, cannot carry cargo, and cannot drill rock. All it does is make a Rock Raider travel faster over land, but the inability to drill or carry cargo makes it easily outshined by the Small Digger and Small Transport Truck, respectively.
Both water vehicles are rendered pointless by the Tunnel Scout. In theory, the ability to carry cargo, Rock Raiders and even small vehicles over water sounds like it'd be very useful. But it's much quicker to just send one Tunnel Scout over the water (or even lava!) and have the pilot simply build a new base on the other side. Now you can teleport everything you need over there in an instant!
All mining vehicles are pretty much useless. Rock Raiders themselves can drill through dirt and loose rock pretty quickly, so vehicles don't do much to speed up the process. While Raiders can't drill through hard rock, it takes most vehicles so long to do this, that you may as well just have an explosives expert place some dynamite there instead. The Chrome Crusher is the one exception as, even without upgraded drills, it can punch through hard rock in two seconds.
Ugly Cute: As long as they are not invading your base, the Slimy Slugs are actually kind of cute, especially in the cutscenes. The way one Slimy Slug smiles and wags its tail when Axle is waving an Energy Crystal, and the way another Slimy Slug sadly shakes its head after watching Axle and Docs drive into the abyss... it's just too cute!
Unwinnable by Insanity: Missions can be made impossible to complete, by laying out the entire floor with power paths and thus running out of ore, since ore cannot be recovered from power paths.
The level Explosive Action can be rendered unwinnable by teleporting the Small Digger you were supposed to recover back up to the LMS Explorer. What you're supposed to do is have a Rock Raider drive it back to your base. And then it gets teleported back up to the LMS Explorer.
The PlayStation Game Provided Examples of (Tropes from the PC Game are not mentioned unless different):