Here's a list of Achievements in FFV and how to unlock them. In this game, they are deceptively easy, and don't take up too much time, with the exception of several which can be missed and require replays.
Unlocking all achievements gives a Master Achievement. As for getting any at all...well, there's personal reward, and it boosts your account, I suppose? Oh well. Points refers to the iOS value. Android achievements give account EXP instead.
Many achievements are unlocked simply by playing through FFV's storyline. At the completion of the game, they will be unlocked. There are 26*(assuming I counted correctly) achievements that are unlocked through these means. Coupled with the Customer Appreciation, those are 27 achievements unlocked just by playing through and beating the game.
Two achievements for the Final Boss. Both are easy enough.
Defeat him with all characters surviving for "The Real Letter".
Run away from him for "Forgot Something?"
And done. To clarify: to run away from him, when you are able to walk up to tree Exdeath and fight him (after the scene where you escape the Void to go fight him), then leave the dungeon. It doesn't mean to Escape from the battle, as that's impossible.
While the Treasure Hunter is difficult and can be missed, other achievements for getting Treasures are often hard to miss. Either way, that's what full game walkthroughs are for listing, not this page.
The Hunter treasures for killing enemies are very easy. You will unlock those without much effort, most likely. However, Bestiary achievements are unlocked by filling up the Bestiary with the enemy species you've killed.
This one is an annoying achievement. Many enemies in the game are missable. To ensure you get them all is a nightmare. Watch out for the Tower on World Two, that contains several missable enemies in a time when you are likely to run away from fights. It's straight forward when it comes to knowing what to do, it's just annoying to do it.
Grinding ABP for Jobs is a longer task, but once the game is complete, it's not difficult at all. I have more in depth tips here, but I'll list some for you regardless.
To get the achievements, one must master each Job with each character. Bartz, Lenna, Krile and Faris all need to master each Job. Doing that often involves a trip to the harder part of the Rift. So near the final boss, kill the enemies. The Movers are the best, but almost every enemy gives very high amounts of ABP there. It should not take long, overall. The main problem is that the enemies are very hard, so bring lots of Cottages. It takes time and dedication, but it's not hard at all.
Grinding to get each character to Level 99 has always been a notoriously hard task in Final Fantasy. Well, take a trip to, once again, the Rift. This achievement is doable as soon as the Cannoneer as mastered, as then, any Freelancer or Mime has EXP Up and can grind much faster. I like to do it after I have mastered every single job. This one is a bit more tedious than Job grinding, but if you're really pro mlg hardkore gam3r, then you won't find it too difficult. If not, well, it's about how much time you have on your hands, more than it is about how difficult a challenge it is.
Everything else(absorbs EVERY element but Lightning)
Omega, or Omega Weapon, is a name of a type of superboss in almost every Final Fantasy game. And this game was where he notoriously made his debut. To fight this, you need to be very well prepared both in game and mentally, as this can take several tries. Even the most prepared of parties have difficulty. Do not be fooled by the normal battle music playing, this boss is way harder than a normal battle. Rapid Fire and Spellblade on two Freelancers, two blade weapons on each Freelancer, and Coral Rings are what you need.
The key is mostly to survive three turns. You need to Thundaga Blade on two Freelancers, then Rapid Fire with them. Your Mime should have White Magic and Time Magic. Hastega first, of course. If you have any spare turns, which is unlikely, Dualcast Meteor or Bahamut (neither do a whole lot). Otherwise, Curaga, Arise, anything and everything to save you from this guy. He hits hard. I would normally say "don't bother with Curaga and focus on Arise", but if you do that, you can easily be killed on low HP. Coral Rings on everyone to avoid Atomic Ray among other things. Oh, and Rocket Punch? It goes through Ribbon. If you lose both of your Dual-Wielding Spellblading Freelancers, you're toast.
Just keep calm and fight on. And excuse my ridiculous meme spouting. Omega in this game is really damn cool I must say, giant robots are always awesome. But he's also a huge pain to fight. It's down to luck, skill and preparation. The chances of everyone being alive when it is defeated are minimal. Oh, and when you beat it, you get an Omega Badge for brag rights. Mobile version gets a better brag right prize (an achievement).
Shinryu is such a ridiculously hard boss that he became famous for his difficulty. So famous, in fact, that he has made appearances in other games in the series. In the original release, Shinryu was the hardest boss. He is harder than Omega for a few reasons: has no elemental weakness (Spellblade, Rapid Fire and Dual Wield do nothing to him), requires different kind of preparation to Omega, is further from a Save Point and has Maelstrom. Don't worry, unlike Omega, he won't Confuse you through Ribbon or take someone out of the fight with Encircle. Shinryu doesn't have tons of disables to your party, but he has a greater disable, killing them.
Whether you can defeat him or not depends almost soley on your ability to Steal four Dragon Lances, and I say four as an almost minimum. You will need two Freelancers with the Dragoon's Jump and the Ninja's Dual-Wield. The other two party members are fine using useful spells like Mighty Guard, White Wind, Curaga, and Summons of Bahamut are also amazingly nice if you get a turn in between. Coral Rings are absolutely essential for blocking some of the magic, do NOT skip them.
Your primary source of damage comes from Jump. Luckily, anyone who casts Jump becomes immune to any source of damage for a few turns. You can breathe a sign or two of relief whenever you get Jump off without dyigng. Just a few Jumping turns, and eventually Shinryu should finally fall.
Other than everything that Omega Mk. I had, Omega Mk. II has several new tricks to watch out for. He also has a very annoying "Remedy" which can heal himself. Yep, you're in for a tough ride. But it's nothing you can't handle. Will take several tries. There are a few ways to beat this boss, but honestly I think the best way is to use a similar tactic to Omega Mk.I, so get your Spellbladers and Rapid Firers ready.
Omega Mk. II's main new point of difficulty is not his new attacks, but his weakness changing. Get the wrong one, and you're pretty much screwed. Anyway, when he moves Right his weakness is Fire, when he moves left his weakness is Ice, and up or down, his weakness is Lightning. You can tell from his flight patterns this way, no need to use Libra. With that in mind, same ol' strategy, but change things up. As soon as he is hit by his weakness, he will change weakness. So keep one Rapid Firer/Spellblader on reserve to instantly Spellblade to the new weakness soon as he does.
You'll have to survive a few turns to exploit his weakness, but it's well worth it. While he has 10,000 more HP than he used to, you also have more powerful weapons and higher stats, so it shouldn't take much longer. If you know what you're doing, and if you're lucky enough to survive the first few turns, you'll be fine. If you go in blind, you're screwed. Thanks to me, you didn't go in blind.
While there are no new real spins on this fight compared to Shinryu like going from Omega to Omega Mk.II, Neo Shinryu is much harder. Do you have 6 Dragon Lances? Good, you have a chance. Do you have Coral Rings on everyone? Awesome, you resist several of Shinryu's attacks. His physicals will one hit you unless you have about 9,999 HP, and even then can kill you - you shouldn't have that much HP, probably. Shinryu has Earthquake, an almost guarenteed kill, but you can not rely on Mighty Guard, just Float everyone before the battle. I would definitely say have the Samurai and Ninja job mastered on a few, that Evasion is almost essential, Golem cannot save you at all. Oh, and if you want another Ribbon, make that Mime who is Jumping a Freelancer instead.
This battle is all about surviving two turns or so. When you begin the battle, Shinryu will cast "Mighty Guard". You can Dispel it, but if you have Dragon Lances you can deal 9,999 damage to him twice in one Jump anyway. After he opens with Maelstrom, if he casts Blaze, you're safe with Coral Rings; if he casts Ice Storm, restart. Unfortunately, you have no choice but to throw all your eggs in one basket for this one. Do your best to get a Hastega in early. Your strategy is to Jump with two Freelancers, and have a third Mime with two Lances just Mimic that. And try to do that twice with three. On death, he'll cast Giga Flare and Meteor. Hopefully, your Dragoon Jumps can avoid that.
If you get away with all of that, the battle is won. This battle is ridiculously hard, though, and will take several tries. Probably more than Omega Mk.II. But just know that once you've killed the bastard, you've defeated the single hardest boss in the game. And one of the hardest in the entire series.
Screw Enuo, this geezeer is Exdeath's dad. Lalalala I can't hear your "he has no ties to Exdeath" argument they're both Void-a-holics and have the same battle theme. Anyway, Spellblade and Rapid Fire should do you fine, but you might want toput up Ribbons. I say this is "very hard" because he's harder than Guardian.
Unlike Omega Mk.II and Shinryu, Enuo comes without his own particular strategy, you just need to defeat hi your own way. Whether that's spams of Bahamut Dualcasts, Flare Blade Rapid Fires, Finishers, or whatever, this boss rules because not only does he have an incredibly badass sprite, there's no strategy other than "put up Mighty Guard, put up Hastega, and do what you like". You probably don't want to use Rapid Fire, as several parts of his body absorb that, so if you ask me, the old trust Attack is the way to go.
Do not underestimate him though, after his "The power of the Void is increasing!" especially, you really want to watch out. You probably want to Dualcast Curaga often. He doesn't have any moves you've not seen, but moves from Omega Mk.II and Neo Shinryu do incorporate into this guy. He'll take several tries but it's a really fun throwback to the Neo Exeath days, complete with the same amazing final boss theme. Ah, I love this boss. Doesn't disappoint in the slightest.
The Cloister of the Dead dungeon is basically a challenge where you defeat all the past bosses of the game except superbosses and final bosses. Surprisingly difficult, but mostly because of how much MP it uses. Bring lots of Ethers and/or Elixirs to remedy this and you shouldn't have too big a deal. Cloister covered in greater detail in the walkthrough.