Another deal-breaker might be the playtime; in about ten hours, you can finish off the game. There's just not enough sustainable content. That's accounting for side quests, as well, which are practically all fetch quests. Towards the end of the game, the main quest have an option for alignment, and more decisions like these would have been a welcome addition earlier in the campaign. Dialogue also could have benefitted from letting choice matter; what's the point in choosing an option if it's the only one the game offers?
Heroes of Ruin's biggest boast is its ability to let you connect online with friends or others around the world, but it simply allows you to endure the lackluster campaign with friends. And if the dungeons or bosses aren't anything special, then what's the motivation to play through these same drab dungeons over and over again? For now, the only thing offering motivation to keep playing is new gear, as there are new daily and weekly challenges to complete that offer Valor. Valor is special currency that can be spent on equipment infused with relics, which add special perks. The only way to obtain valor is by enlisting in these special challenges. There's also a trader's network that enables you to trade surplus gear through StreetPass.
Heroes of Ruin is ultimately just another run-of-the-mill experience, which is truly unfortunate considering it's pretty much the only title in the genre on Nintendo’s hardware over a year after launch. Its potential is totally squandered on a highly forgettable experience. Heroes of Ruin doesn't do anything to make the genre sparkle anew, and with its short span of content, you won't exactly find yourself locked in for too long. Heroes of Ruin has no shining areas; it's barely competent, and despite its status as the only online-enabled hack-and-slash for the 3DS, you’d be better off waiting for someone else to execute the genre better.