Ok, my first and biggest problem is that this game doesn't follow air hockey, it feels like soccer, because in air hockey, the puck is quick the puck-hitter (don't know what it's called) should NOT pass the half line.
Then furthermore, the user and the AI go through each other, which is annoying, it shatters any sense of realism, then you would assume that an air hockey game would implement/use the mouse in order to move, but it uses arrow keys, which further ruins any and all immersion.
No music is annoying, though I prefer to play without music if the music doesn't fit the game, though for this, I would just search up the loop for what they use at the arcades. The same with no sfx, if it works with the game, no problem, if it doesn't, then don't add em in.
You've at least got a working-ish game, though you really haven't accomplished a real feeling of air hockey. Though even if you succeeded, I would rate it at 3 at best, simply because this has been done heaps, in many different ways, with upgrades as well, so its idea isn't new.
But overall, you've got a somewhat alright game, and if you want to fix it, I'd hope you do well.