My biggest beef with Rhythm Thief is that the gyroscope motion missions are frustrating. Thankfully they're mostly optional. Otherwise, it's a good Elite Beat Agents substitute with some really good music and a wacky plot set in Paris.
I'll throw in the Denpa Men series but honestly you're better off playing The Denpa Men 3 since the sequels get progressively better by leaps and bounds. They're all dungeon crawlers that run well past the 100+ hour time if you want to do everything but they're good. Save data from prior DM games unlocks bonus goodies in later games.
As for other recommendations not mentioned yet:
I'll throw in the Denpa Men series but honestly you're better off playing The Denpa Men 3 since the sequels get progressively better by leaps and bounds. They're all dungeon crawlers that run well past the 100+ hour time if you want to do everything but they're good. Save data from prior DM games unlocks bonus goodies in later games.
As for other recommendations not mentioned yet:
- Kung Fu Rabbit is a cute little platformer game that's cheap (At least by USD standards. Not sure about AUD.)
- Liberation Maiden is a solid shmump in the vein of Panzer Dragoon in that it's on rails
- The Mercenaries Saga trilogy is decent from what I heard and played the demo. It's a poor man's Final Fantasy Tactics but a solid one at that. It's also coming to Switch if you have one so I would wait.
- Ai Race Xeno is the definitive game pf the series to play if you liked the Wipe Out series
- LBX: Little Battlers Experience is an underrated gem that usually goes on sale. It's a mecha RPG where you mix and match robot parts
- Radiant Historia: Perfect Chronology should not be missed (play the demo on Easy; progress carries over to the full game)
- Strange Journey: Redux is another Atlus title that's easily a must grab
- Kirby's Dreamland (?) is enhanced for 3DS and is easily worth the recommendation
- Kami is a relaxing origami puzzle game that's dirt cheap
- Rage of The Gladiator is a good Punch Out clone with a Greek mythology twist and RPG elements. It's grindy at times if you want to get all 3 medals and upgrade your skills.
- Super Street Fighter IV is quite solid on 3DS. You can still find matches online too.
- Steel Diver: Submarine Wars is a solid free MP game.
- Donkey Kong Country Returns for 3DS is quite good and makes improvements on the Wii version. Plus it has has no waggle to roll (!!)
Avoid Crashmo, Pushmo's spin-off. I heard puzzles get quite frustrating.
