Dungeon Hearts brings together a lot of things I like, mostly match 3 and music mechanics. What it lacks, and what led me to purchase this in the first place, is the promised RPG elements. Yes, there are special attacks of increasing power, and they certainly put the word "Dungeon" in the title, but there's absolutely no sense of permanence to the proceedings.
A small horde of games within this genre have a better grasp on how to keep the player engaged across multiple sessions. From the extreme cases, like Puzzle Quest, where you have a full customizable character, to the Infinity Blade series, which lets you gain levels through your gear, all the way down to Jetpack Joyride, which gives you tiered levels of achievements, many of these budget-priced games give you some permanent improvement or upgrade between the short, impulsive game sessions.
The RPG trappings would suggest something more, like a leveling system, or an item system, or the ability to really customize characters. It ends up having the worst features of a Rogue-like or an old arcade game, without the individual playthroughs having enough satisfaction to justify the format.
While it's ultimately nice looking and clever in premise, there's just not much to keep a player coming back after the first few times. There are far more long-lasting experiences you can get for this amount of money.