Repetitive gameplay. Although the main objective is to hunt and kill Jaws, they padded out what little gameplay there is by shoehorning in a pointless RPG element. You're unable to kill Jaws at the start because Jaws always starts with full health when you encounter him no matter how much damage you did to him in previous fights and you're not strong enough yet to defeat him in one fight. To defeat Jaws you have to level up multiple times with shells you pick up from killing stingrays and jellyfish till you're finally strong enough to kill Jaws before he escapes.
The game can be completed in less than 10 minutes once the player has figured out how to progress.
Every time you go underwater there's a time limit that's never visible onscreen, which means if you're fighting Jaws you have to kill him very quickly or he'll regain all his health and you have to find him again.
You die in one hit unless you get the submarine upgrade.
The motion-tracking upgrade is pointless because you already start the game with ways of tracking Jaws! The music gets louder the closer he is to you and sometimes his fin pops up above the water.
The final battle with Jaws; after depleting all his health you have to strike him with the prow of the boat and time it just right. You get only 3 chances to hit him and if you miss all 3 times, Jaws regains all his health and you have to fight him all over again.
Every time you die, your experience level decreases by one (unless if it's at the very minimum), and you lose half your shells.
The bonus stages. Not only do they randomly interrupt the gameplay with zero warning, but they're also boring and you get no useful reward for playing them other than just getting more points.
The ending is unsatisfying and consists of a 5 second-long scene.
Good music composed by Shinichi Sakamoto.
The title screen and final battle have a decent rendition of the Jaws theme.
Decent graphics at this time.
Despite these problems above, Jaws actually managed to get positive review from players with an 4.7/5 on eBay, and an 3.7/5 on OldGameShelf.com.