Chrono Trigger was originally released for the SNES system. However, a downgrade of the game was created for this NES-System.
The Graphics of Chrono Trigger (NES)
The number of sprites and tiles they were able to fit into a single cartridge is actually pretty impressive, although some of the character sprites are wildly inaccurate. In fact, up until the boss fight with Magus, all the bits that people remember about Chrono Trigger are there. All characters, all important locations and the plot can be found in the downgrade. Although some of the areas have been changed: in Magus' castle, Flea's area is a puffy cloud area with chains bridging gaps, while in game it was just a normal area of the castle. There are also some graphic glitches, but most of them are barely noticeable.
Music
The music, despite being rendered in a poor sound engine, is pretty close to the original. The battle theme, the theme for AD 1000, the theme for AD 600, most of it is there. Unfortunately, the future theme is not present, being replaced by the AD 600 theme. No attempt was made to bring the sound effects close to the original, and as such they don't sound like they did in the SNES original.
Gameplay
The gameplay shows exactly what went wrong when porting this game. Even if the SNES had weak processors for its time, it was obviously more than twice as powerful as the NES before it, and even the Genesis could spin circles around the NES every day. The downgrade took advantage of features and performance that the NES system just didn't have.
The intro
The game starts out as it should, with the same intro as the SNES version. All of the animation has been stripped out to save space, but it's still faithful to the original game and shows that the developers tried to make it as faithful to the original as possible. You could almost think it was made as a project by fans, until you realize that the entire game is in Chinese. It's still playable, but it really takes away from the RPG experience if you can't read the dialogue.
No overworld map
As soon as you leave Crono's house, you'll find something horrible: the overworld map has completely disappeared. In its place are roads that will take you to all the locations present in this version, surrounded by impassable grass. It has thus been downgraded quite a bit, although it saves space. The minigames from the original version are gone.
Game Engine Limitations
The game engine is the same that these developers use for almost all of their RPGs. For whatever reason, the limitations of the game engine, by the way, are really starting to make themselves felt. For example, the time travel animation is now a two-screen animation that takes up about 10% of the screen and doesn't look the least bit impressive. A similar approach is taken for the cutscene revealing the planet's future, although it is instead an actual animation made up of different screens. The "animation" effect is ruined by the lackluster graphic design and the fact that it has to fade to black and load another frame, then fade to black and load the next frame, etc.
the story
Due to the language barrier, it's not possible to say exactly how close the story is to the real game. Unfortunately, it's still not safe from typos. At one point AD 1000 is referred to as AD 10000.
The game balance
Game balance, which is one of the most important parts of an RPG, is usually badly flawed in some of these Chinese RPGs. In some of them, it's so bad that you can't even get through without the first area of the game. Enemies drop large amounts of experience and money, and it usually doesn't take too much EXP to level up, which replenishes that character's HP and MP. However, if you're not careful, it's possible that you'll find yourself in a situation where you're too weak to fend off the enemies around you.
The combat system
The combat system is definitely more advanced than any other Final Fantasy game on the NES. It has an ATB battle system just like the original game. However, the limits of the game quickly become clear. For one thing, combat is terribly slow until your characters have a high enough Speed stat. You have to wait more than 10 seconds for the bar to fill up, and you can't select commands while an animation is playing, even if the gauge is full. Also, the game doesn't pause when you select commands, items, or techniques, meaning you'll have to rush to make sure an item isn't administered too late.
Conclusion
Finally, for the most part the game is actually pretty good. The shortcomings that it has are sometimes annoying. They are overshadowed by the sheer amount of effort that went into porting it to a cartridge for a vastly inferior system. It's actually a bit surprising that no one has tried to translate and improve this game.