Game Breaker / Rune Factory 5

• Siren, a regular enemy in the game, originally had an absurdly high attack and magic attack (high enough to rival bosses), resisted just about every attack, and players could fill their party with 3 of them. She has since been nerfed in a patch, but is still very powerful, nonetheless. Many players who casually tamed a siren accidentally made the rest of the game a cakewalk without realizing it.
  • Monster taming, with enough time and investment, can make the game much, much easier. For example: tame a Red, a fairy rarely found deep in Kelve Volcanic Region, get a few FP and levels with it and Red will crush the Kraken, the next boss, almost effortlessly even on Hard difficulty.
• If Elsje is in the player's party and the player character is low in health, she will throw food at the player character to instantly restore health. If the food misses the player character, then it falls to the ground and can be picked up. These food items include royal curry and other late-game dishes that not only have powerful effects on the player character, but also sell for a lot. Elsje never runs out of food to throw and what she throws is random, so Elsje can be used to farm expensive dishes indefinitely as long as the player character is low on health.
• If the player gifts villagers 5 homemade gifts, they will give a gift in return. Some villagers give better returns than others; Terry can give a random accessory, such as the experience-boosting Heart Pendant, while Darroch will give hammers weapons, which can include a Gigant Hammer+, which is a post-game tier weapon, leagues stronger than anything you can make yourself before the end of the story. Items such as these can make the early game a breeze. Alternatively, they also sell for a lot in-game currency, which also helps makes the early game easy.
• Magic can be very, very powerful here. Gatling Comet spell is incredibly powerful, hits a very large area and costs very little RP for late game. It allows you to nuke anything that isn't fireproof at safe distances with near impunity and unlike other fire spells you don't have to keep pressing buttons to fire it rapidly.
  • The Impact Laser is less powerful, but it's a huge water beam that you can keep firing for as long as you hold the button. This magic allows you to basically snipe enemies from very far and unless it's a "huge" enemy they'll be stunlocked. It also pierces targets, so anything lined up will get hit too and you can readjust your aim after firing it.
• The Wind Cloak is an armor that can be made as early as Kelve Lava Caves: Depths is available. Why is it game breaking? It has almost three times as much defense as the next armor and far outclasses anything up until stuff you can make post-game. This made more sense in the previous game, when the materials to craft it were correspondingly hard to get, but there's no such balance in this one. Wearing it basically makes you take next to no damage for the rest of Chapter 2.
• High level recipes and failures. No, seriously. You can force leveling up any crafting skill (Cooking, Forging, Crafting) by selecting a recipe that's way above your current skill level and waste common resources like Iron to produce Scrap Metal, Object X or Failed Dishes. Then you can repeat the loop with said failed items needing only food to replenish your RP. Do this with something like a Golden Turnip Staff, which needs a Forging skill of 80, a Heart Pendant and you can get something like 5 levels per 30+ failures, it does get more difficult as you close in, but you can easily get your crafting skills as far as 80, when recipes start demanding "+ Breads", before the first Summer if you're dedicated enough.
• The Nine-Tailed Fox is the first boss, is only level 5 (meaning players can easily be at a high enough level to be able to tame it), has all of the immunities that bosses have (immune to all status effects, including instant fainting), many resistances, high stats as expected of a boss, and can be tamed using one of its own item drops. It can be obtained early on and relatively easily for a boss monster. Plus, it can be rode upon, which temporarily grants the protagonist its stats and defenses (and faster walking speed). It is very powerful monster to have, to say the least. Also, while riding it, 2 of its attacks use magic (with one of them being similar to Gatling Comet spell mentioned above) without using RP or HP.
• Object X is a weirdly useful item that can be easily mass produced even at Chemistry Level 0 by failing any recipe. If you throw an Object X at a non-boss enemy it'll inflict every status ailment possible and this works even for enemies that you would normally deal no damage against, including most of Wanted Monsters that can easily be ridiculously overleveled for an early game player. Only a few rare enemy types like Big Mucks, Golems and Ghosts resist the effects of Object X.
• Fist weapons enables the player to use a grab attack after striking a non-boss enemy even if you deal zero damage to it. What's the big deal about it? 1) Grab attacks are abnormally powerful and deal far higher damage than any regular attack being easily able to one-shot most enemies that aren't way above your level even on Hard difficulty. 2) You're fully invincible while performing them. 3) You can easily grab the enemy you tossed again and again. 4) The size of area a grab attack affects depends on the size of the monster, and any non-boss monster can be grabbed, if you grab a huge monster like Golems and Dragons you can easily throw them and defeat several monsters trying to pile on you. 5) Grab attacks are much easier to use than the clunky Fist ultimate attack and require no weapon skill level to perform. Their RP cost also quickly becomes negligible.