Latale
It's a free-to-play Korean 2D Side-Scrolling MMORPG sort of like Maplestory but with higher res sprites for those of you who don't know
1. Bad Translation- It's a poorly translated game. It is very difficult to follow, or even care about the story due to how poorly translated it is. It can range from comically bad, to down right unintelligible. I wouldn't be surprised if their method of translating it was just putting it all through an online translator.
2. The difficulty of obtaining and enchanting equipment- The standard armors, weapons and accessories you can get regularly in the game via purchasing them in shops just don't cut it because enemies will wipe the floor with you if you are under equipped and the standard armors generally will not match up to the enemies. The special armors, can be expensive, and difficult to come by, and even then, just having the armor won't make you strong. When the armor doesn't cut it, your next option is to enchant it with puzzles to make it stronger. Puzzles range in level from 1-12 and there are puzzles like strength puzzles and speed puzzles... etc Every time you enchant with a puzzle, there is a realistic chance of you failing to enchant, and when enchantment fails, whatever armor or weapon you were enchanting gets destroyed. No salvaging it, it is gone for good. Considering the necessity of well-enchanted rare armor mid-late game, it's ridiculous how hard it can be just to get it to an acceptable strength.
3. PVP- The game tries to balance its pvp, but fails miserably. For example, the level cap is at about 200, and a lot of high level people like to pvp. Anyone can pvp and there is no system to match you up with people at your level. They tried drastically raising the stats of people from level 1-80, but they still pale in comparison to the higher level characters. I was about level 128, and tried fighting a level 196 character. There was no balance at all. Pretty much all of his attacks one-hit KO'ed me. After a few minutes, (There are about 5 minutes in each round of pvp) he got bored of kicking my ass and just stood there and walled me. I was attacking him with every single skill I had, and he was casually regenerating hp faster than I could deal damage.
I love this game, but it just makes it so difficult to play sometimes.