OK, a few things. First, I like the overall concept. I have an interest in this type of thing and have gone into some deep dives reading non-fiction books on submarine warfare in WWII. So I’m glad this exists and overall, I like it.
A few things stand out though. First, probably the most obvious issue is that the enemy isn’t cleared off the map until the torpedo sound is finished exploding. What this means is that you can keep pelting an enemy with torpedoes, but he’s not dying and you don’t know why. After all, one single torpedo can cut a sub in half. At first, I thought it was the arcade nature of the game and was content to leave it be, but then I noticed that enemy hull sounds would disappear only when the exploding sound finished.
Next is the fact that the enemy hull sounds loop badly. Now, normally, I wouldn’t ding someone for this, because I recognize there are some folks here who have never worked in audio before. The reason I am mentioning it in this particular case is that when the enemies start piling up, I can just wait for one of their hull sounds to pop when it loops back to the start and lock in on it.
Somewhat related to the last point, there’s really not that much reason to use sonar in the game. You can just listen for the hull sounds and target based on that. The only time I used sonar is when a bunch of enemies were scattered in such a way as to make it seem as though one of them was taking a big swath out of the stereo field. Not needing to use sonar means you’re practically immune from damage. I got hit only once, for instance, because of how rarely I used the sonar.
One minor point is that you have unlimited torpedoes, which means you can indiscriminately turn and shoot without having to worry about much. I would recommend limiting the use amount of torpedoes per level, as well as making the enemies capable of fixing on a fired torpedo. While it wouldn’t be your exact position like the sonar fix is, it would give the player a reason to hold back until they had a clean shot.
Another thing I might recommend is making the player have to watch their speed. In submarine warfare, cavitation is noisy and dangerous. In this game, perhaps you could hold the arrow until you heard a beep, and then you’d have to tap the arrow to stay just below the point of cavitation, or risk the enemy getting a fix on you.
I don’t know how many levels there are, but I played up until it turned into 6 stationary enemies, then stopped because it stopped being fun. I just wasn’t being challenged.
One last thing, and sorry that got so long. There is no consequence for getting right up in a baddy’s face and blasting away. There really should be some kind of spillover damage you take if you do that.