Thoughts on Hyperdimension Neptunia U: Action Unleashed? I've never played any game in the series.
It's a spin-off that's totally different from any of the other games in the series (aside from the story and voice acting, which are all Hyperdimension Neptunia, along with the inclusion of the HDD powers, lily rank powers, and magic attacks from the other games). It's not an rpg at all aside from leveling up and being able to assign special attributes that raise/lower stats. They brought on Tamsoft because of their work with Senran Kagura and Onechanbara and basically made it a hack-and-slash/beat-em-up with a clothes ripping mechanic (i.e. clothes rip when you take damage).
It's pretty fun, but it does get repetitive, especially by the time you get to the extensive post-game content. You get...err...10 characters from the series and can use 2 on a team (switching between them), and you're pretty much just combo-ing (or button mashing) mobs of enemies until you've killed enough or the boss-level enemies spawn and you take them out. Or clearing out one area so the next opens and getting to the end. Those are divided into missions, sometimes with special requirements like using certain characters. And that's about the extent of it. It's really easy for the most part...pretty much mindless button-mashing hack-and-slash fun.