Hi LtCoyote, thanks for playing this game! Yes one of the mistakes I made during this jam is that I spent too little time on level designing (I remember that I didn't sleep on the last day of the jam, spent 16 or 18 hours that day developing haha). The sound/noise system in this game actually works like:

1. The zombies/ghosts chase the last sound they hear, or when the player gets too close, they start to chase the player.

2. The sound circles would reach their real radius except the footsteps, which was a bit too distracting when I set it to reach the full radius instead of currently radius / 2.0, I think a better solution would be to decouple the opacity with the circles' lifespan, but unfortunately didn't have enough time to implement.

3. The Lift and Battery Charger emits sound periodically (currently 5 seconds), so they would only attract zombies when there are yellow circles.

4. The zombies can actually pass each other, I think it's kinda cool and would make them more scary and ghost like. Byproduct is they will congregate next to a sound source, especially if the sound source is static, I think maybe some random variation could solve this.

Glad you find the game atmospheric :D ! Audios really makes a difference on games! I think the invisible zombies add to the tension as well.

Part of the reasons why I make jam games, to be honest, is to prototype game ideas and to see if they are suitable for a complete game. If you are interested, I'd like to hear your opinions on how to expand these mechanics as well. I think the game lacks some vital gameplay elements. Currently if I'd expand on this game, I'd add more player progressions, maybe base building, like collecting resources ( maybe Loot System? ) to build things like Spot Light which can also detect zombies, or defence robots/turrets, etc.

And about the next/future games, currently I am thinking about experimenting with emergent gameplay, and making roguelikes again, which probably saves the headaches of level designing.  Maybe port some mechanics, and focus on gameplay instead of programming. I used to be afraid of players getting too powerful / go out of the intended way, but now I think it should be encouraged, I want to add a ton of powerful and different abilities for players to freely combine in the next game! Thanks for playing!

Thanks for playing! Yea I spent too much time on system implementations and left only some hours for level design and playtesting, my initial plan is to (maybe procedually generate) some indoor rooms with corridor and open grounds, and gradually introduce battery charging in first level, using grenade to draw enemies' attentions at second level... Currently I guess I will tweak the existing levels and maybe add some levels between Tutorial and Resident, glad you like the noise system! :)

Thanks for the kind words! The sound system is the first thing I implemented in this game, I think it raises tension pretty well incorporated with Light Only Zombies, glad you like it! :)