Venture/YMMV

* That One Achievement:
** "Open Railway." The goal: "travel 3280.8399 feet by mine trolley from your starting point". It requires obscene amounts of materials, and it needs to be 1000 meters away on a straight rope. It is easy, but the engineering and resources required are buggy. One Mine Trolley costs 5 Steel Alloys. 52.4934 feet worth of Mine Trolley Rail is 6 Metallic Ingots. That is 378 Metal Alloys, right there. If you find abandoned mines, however, the abandoned rails can be collected for no cost. Of course, the trolley will not travel forever, so you will need boosters. That is 6 Gold Ingots and one Scarlet Rock for 6 tracks. Then there is the items needed to activate the tracks, which is more resources. And after all of that, you need to construct the whole rail, which involves a lot of digging, clearing, placing, and testing the whole thing to make sure it works. But on the bright side, as long as the rail is active, it will work if the badge happens to be cleared. What really kills, though, is that every background update wipes your trophies. Hope you saved that world with the 3280.8399 foot rail.
** "Sniper Elite" is Broken By Design since it requires you to murder a Shooter with a bullet from a 164.042 foot distance. Unlike bullets in other games, Venture's bullets follow the laws of gravity overly where the bullet is pulled down by gravity as it progresses. Bullets lose altitude as they travel and it is hard to aim accordingly due to the Shooter never staying. You will need to snipe from a cliff or mountain to compensate for the gravity, but it is still impossible to do since Shooter never stand still and you can burn through all of your bullets hitting a far Bulls Eye.
** "Wundo Phuck" requires having all 20 modifiers in survival at the same time. The worst part is that requires having Mine Sleep and Telekinesis at the same time: those two status effects are only inflicted by a creature who only lives at the bottom of the sea and a creature who only lives in a hovering isle in the middle of nowhere, respectively. And then you would need to be inflicted with Decayer at the same time, which requires a creature which is found far from the two aforementioned creatures, or another creature who is summoned but kills everything, including those two aforementioned creatures. Even then, you will also need to spend a lot of resources in building beacons and brewing elixirs.
** "Serious Determination" which would be a "Fuck This Achievement" if that trope existed, but anyway. You must waste two diamonds on a gem pitchfork, something you would never craft if it was not because of the badge. And that is not the end: you must use it until it snaps, which will require a lot of time (it can plow 1,562 meters of land) unless you till every single meter of earth you see (that being much more than you would till in a generic, or even a little sizable farm) or use it to hit creatures (which drains durability quick, but pitchforks are extremely weak in battle).
* That One Boss:
** The Wyvern falls into this category, notable in that it was the only boss before Venture: Breathtaking Fear's corresponding update was released. It flies out of blade range, loves to knock the player off of things, always off of the of the Wyve and into the void, and regenerates health whenever it goes on undamaged Wyve Quartz, located on the tops of super towering obsidian collumns. The Wyvern also has the ability to barf magic acid descaler, and becomes immune to bullets when it perches on top of the inactive exit, making it invincible at that stage in single player unless it assassinates the Wyveslenders around it.
** The Decayer is a worse offender. It is capable of destroying you and everyone else before the combat even starts by releasing an enormous detonation from its body. The actual battle is worse, it flies around and pukes explosive craniums that also decompose any target it hits, draining their health bars, but unlike normal acid, this will murder the target instead of leaving them with 1 HP, and thank you, Decayer being a triplefaced creature, it can spam the craniums as well as attacking multiple targets simultaneously. You can shoot it with bullets in the first part of the batlte, but after it is half dead, it gains a bubble shield that makes it immune to said bullets, leaving you with Splash Potions and your broadswords. And if you hide? The Decayer will consume objects you are hiding behind. Did we mention it has a Healing Factor?
* That One Level:
*# When you light up a new cavern, only to discover a fall into water, or worse: magma yawning below a series of unlit dens that suddenly storm a horde of violent beasts down onto your face, then you will understand.
*# A non varying case would be Hell, a molten desert that is impossible to navigate due to containing a literal ocean of molten rock, a handful of strong creatures, and giant clusters of Hell Rack that make it impossible to find Hell Strongholds, which contain creatures that drop items necessary to progress.
* That One Sidequest: Leverets are much trickier to breed than any other calm creature in the game. Breeding a creature briefly causes it to ignore the luring effects of its breeding food, as does going out of their luring range. Not only do Leverets run away at breakneck speed from players not holding dandelions or vegetables, but they also have a small lure radius unlike other tranquil creatures, who tend stand around and walk about aimlessly. In order to get all varieties of Leverets, you will need to go to a multitude of ecosystems, several of which are inhabited by Canids, who love eating Leverets. Whipping out your blade to deal with the Canids before they assassinate your Leverets leaves them scurrying about, and then you need to slowly lure them back to you. Thankfully, all of these problems can be simplified by attaching the Leverets to leads, or putting the vegetable or dandelion in your right hand so you can use your left hand to battle.