There is no save state for the game but there are passwords the user can utilize in order to get back to the last stage they progressed to. On top of this the game has unlimited continues, so when the player dies (of which this game is a one hit kill game) they are able to start back a the beginning of the stage as many times as they want. Which quite frankly will happen a lot.
For a classic platformer the controls for this game are spot on, as they need to be since the game is tough. Platforming is responsive and switching gravity works great being that it is necessary for the whole game.
One of if not the first game to utilize reverse gravity in a platformer. The reverse gravity mechanic is used in the game in order to solve puzzles in certain places in certain stages. By reversing the gravity the player is able to walk on the ceiling of stages and platforms, which is necessary in order to progress in the game. Later games like Megaman 5 also used a mechanic like this, but Metal Storm was released a year earlier.
The game features a unique mechanic for a NES game in that it fakes parallax scrolling. The NES was not capable of this technique, but what the developers did was fake it by redrawing the background every frame the character moves in order to make it look as though the background is moving.
This game is tough, extremely tough. Touching an enemy kills you, touching moving doors kills you, falling off the stage kills you, every bullet in the game kills you. Everything pretty much can kill you. It will take much practice to progress in this game, though luckily there are unlimited continues.
Often in the game, when killing an enemy, i the player takes a few steps back the enemy they just killed will re-spawn back to the stage, which can be very frustrating as there are often times that back tracking is helpful.
The game features 2 player simultaneous co-op (much like Contra) where both players go through the stages to defeat bad guys with their Ninja skills. Seeing that other Ninja games for the NES like Ninja Gaiden did not have any co-op, this games makes a great choice for Ninja co-op action on the NES.
An NES game released later in the consoles life cycle, Shadow of the Ninja has a high amount of polish that pushes the boundaries of the console. The graphics are quite solid with animated backgrounds such as rain as well as worthwhile level design and enemy design. The sound in the game is done quite well too with a great soundtrack and good sound effects. All of this adds up to a game that really shines looks and design.
There is a weapon charge move in the game which allows the player to hold down the attack button in order to attack all enemies on the screen. This is really useful in stressful situations where there are too many enemies to handle or are close to death.
Any weapon pickup in the game is limited to just that weapon, which will have to be used until you run out or pick up a different weapon. So that makes for little customization on that front.
There are no extra lives and only 5 continues in the game, this becomes trouble as the game is tough. There are enemies that will run at you constantly in order to knock you off a platform, or into other enemies, on top of this the enemies take multiple hits to kill. While not an impossible game, it is tough and can be frustrating. When playing in co-op mode, those 5 continues are shared, which can make the game tougher at the same time of making it easier due to the second players help.
For being such an old game to see the framework of a morality system used is quite interesting and actually a really nice mechanic. Depending on how you behave in the game (helping people or choosing to not help people) means that your likeness meter will go up. The more this meter goes up the more certain things get unlocked in the game, which gives more access and allows the player to move forward in the story.
For a NES game to feature something like an open world game is quite an accomplishment. The city in the game can take up to half an hour to explore and allows the character to pick and choose what they do. Want to save people from getting mugged, feel free, you can also just let the mugging continue. Want to explore a library, you can do that too. While of course the open world aspects will seem limiting by today's standards, just the fact that an 8 bit game accomplished this is something to behold.
The game has quite a bit of dialog, and this dialog often has corny and amusing jokes in it. It is lighthearted but still done well in a sense that it doesn't go too over the top. For those that are fans of corny humor, this game should appeal.
The menu system can be tough to navigate as it is many boxes inside of boxes, on top of this the item management can also be a pain due to the clunky menus and how many items one needs to manage. While much can be forgiven due to the age of this game and how little was possible in 8bit, it still can be frustrating.
There is zero hand holding in this game meaning it will take a tone of trial and error in order to figure out where to go and what to do. This can also cause some frustration though is any single element to the game is being missed and may take a strategy guide online in order to get unstuck.