Starting a thread for good Vita and 3DS games because there may be some that I'd happen to like but either might never. I bring it up because of Shinobi, while on my buy list, I only recently to get over $25 for free shipping from Amazon and it happened to be a great game.
For platforming fans, though. Shinobi is highly recommended. Extremely precise controls, and while the game is very difficult,for the most part it's actual difficulty, not cheap memorization based difficulty. The only issue I have about the game is the length of the stages. Most of the stages are 15-20 minutes in length, with one being more than 20-35 minutes and having very unforgiving checkpoints for only having five lives before having to restart from the stages beginning. Great and challenge platformer.
Lords of Shadow Mirror of Fate. Mirror of Fate plays a lot like a classic Castlevania title mixed with the exploration of the later games and a 2D version of Lords of Shadow's combat system. Difficulty is also an issue with this game, but unlike Shinobi, it's that checkpoints in this game are too forgiving. The game is best when 100% of everything is acquired, your character is on the max level, and you replay the game on hardcore difficulty. The checkpoints are still forgiving, but there's less checkpoints when you've acquired everything and the difficulty is atleast somewhat challenging at that point. The 3D effect in this game is by far the best of any 3DS game I've played, just turn it off when underwater because it's bad.
Uncharted Fight for Fortune. If you don't like card games, then I can see you not being interested in this game, but if you're interested in card games, don't pass on this game because it's got the Uncharted name. It doesn't have the depth in comparison to card games like Magic the Gathering, but even with its simplistic approach to the genre, there's still a lot of strategy involved in making your deck and what cards you're going to play. It's a pretty cheap game at $4.99.