Nanostray is a bullet-hell game on the Nintendo DS. You pilot your ship through a large variety of locales, with each level having a different aesthetic: jungles, space stations, canyons, asteroid fields, oceans etc.
The graphics are very impressive for the DS. There is plenty of variety in enemy design as well as impressive visual effects. The screen can get quite hectic with bullets filling the screen. The frame-rate does drop on occasion, but not for longer than a second, and it is usually when you have just wiped the screen with a bomb, so it never is the cause of death.
Your ship can take several hits with bullets before being destroyed, but collisions often will take you out in one hit. You can die by crashing into the environment, and it can be a bit confusing to distinguish the background from death-causing objects. It's not a huge problem but can be the cause of a few cheap deaths.
The bosses at the end of each level can be pretty challenging, and you can end up suffering a few cheap deaths at this point. As long as you reach the boss with a couple of lives left, then it shouldn't be a problem.
There is a selection of guns that you can select on the touch-screen and it's a bit troublesome to switch whilst engaging in the action. It's not mandatory to actually switch weapons though. Your main laser is good enough, combined with the limited secondary weapon which is more powerful, and a limited supply of bombs which destroy all on the screen. The secondary weapon can be recharged by collecting the blue coins left behind by destroyed enemies.
Once you get used to the games mechanics, you will start to breeze through the game and it doesn't take too long to get through the Adventure mode. Each level takes 3-7 minutes to complete, so it can feel a little on the short side. Outside the main Adventure mode, you have Arcade mode and Challenge mode. Arcade mode is just the individual levels played with the aim of achieving high scores. You are given a points breakdown and an overall rank, so there's definitely scope to improve your score. Extra points are awarded for sticking with your primary mode of fire, collecting the coins, achieving a high hit accuracy, and taking out all enemies in a wave. In Challenge mode, each challenge sends you back through the same levels but with a new objective. Objectives can be to reach a certain score, or complete the level without the use of bombs.
Nanostray often seems a bit too easy during the main levels, then often feels a bit cheap with the bosses. With a more balanced challenge, I would have been more motivated to replay it. Despite this, Nanostray is a good bullet-hell game and shows what is achievable on the Nintendo DS.