The frame rate is quite choppy for an NES game. It's evident when there are more than two enemies on screen.
Some enemies move around too quickly, and your bullets end up missing them.
The game is extremely difficult. It's very well possible that the first enemy in the game can easily kill you. Make the mistake of going to the 33rd floor and you are ambushed by more terrorists than were in the film, a beginner's trap guaranteed to catch out unwary players.
It can be too rigid to follow the plot of the film: at one point of the game, if the player finds the fire hose and tries to jump off the roof, John McClane will say something like "I'm not crazy to do this, no thanks." Yet, he has no qualms with jumping out of the window and dying instantly. The irony is that John McClane used a firehose to get to one of the floors from the roof and in game this is reserved for near the end should you want to do this the hard way.
If you do die, you have to restart from the beginning, with all of your progress gone.
Enemies are difficult to kill: The guards have crack shots against you, and they will bombard the screen with bullets and stun grenades and reload quickly. Terrorists spray and pray in a large area before taking time to reload. This type of tactical gameplay would be something many players are not prepared for.
The soundtrack is at least decent and plays appropriate music at the right time.
The cutscene graphics are well drawn.
Outside of the generic kill all the terrorists, there are numerous optional objectives: radio the police before the second lock is undone, find the rocket and blueprints to blow up the computer for more time and supplies, find Heinrich when Hans deploys him and take his detonators, etc.
The game is more intelligent, more involved, than the likes of Contra, with multiple endings depending on your actions.
This is one of the first NES games to feature a different ending in the case of both the player character and boss character defeating themselves.