Damn the creepy mood is real, really cool audio and graphics !

My main complaint would be that the game don't incentivize you to increase your score enough, and the simpliest way to survive long is to build a wall fungi (they look like cookies btw, but that's fine, i love cookies.) which blocks bugs indefinitely. But killing bugs is the most important part of the ecosystem, as they produce the flies the spiders eats and turns into mini spiders, they also produce the fungi to distract flies. This means if you don't kill bugs but just block them, the spiders won't do anything and just wait for flies, but there won't be any flies, which means no mini spider and infinite lasting fungi, bringing the game to a pause, nothing happens to you while you have a fungi wall, and it's not super fun. Now the solution could be as simple as to not build such a wall in the first place, but that's where the issue is : you have to. Without it you get attacked by bugs, so you have to kill them, but if you leave the bodies without any fungi you're going to die with the resulting flies, so you have to break their bodies, which makes fungi, turning into a wall very quickly. 

You can as a player let a few bodies turn into flies, that's where the game is the most fun, but this is a very risky action as it canreally easily get out of control - it is the point of the game afterall - but as the only reward for doing so is score points. The score only is a number to track how well you did, but not the actual goal of the game (to me at least, the game wants you to manage the ecosystem, not have a high score), and even if it is, gaining points isn't fun nor interesting on it's own, while the gameplay is.

If keeping the score is something you want, then the game should give the player more reasons to break his defensive fungi wall and let chaos be. Otherwise i think creating a state where the palyer can survive infinitely without doing anything shouldn't be possible, there are several ways this could be done :

• make the fungi disappear on its own
• don't make it block for eternity the bugs : they could destroy it or simply move slowly inside it
• make it really simple to destroy by the player, right now it is as much a barrier against the bugs and flies that it is to the player, having to destroy a huge wall by hand is tiresome and hard to do by accident, while if it was fragile you could accidentaly create a breach in the wall
• change how to produce fungi, maybe a rarer crawler than the basic bug could make it appear when he dies so you don't spawn so many.
• change how to produce flies, the main reason i turned every bugs into fungi, was because i didn't wanted flies, they are very deadly, attacking you but also feeding spiders and destroying your defenses, the only alternative to producing flies is to make fungi, you can't even allow yourself to make flies without first making fungi as they will most definitely kill you

Related to the fungi wall thing, bugs where piling up against it and after some time they started to make a lot of noise, this could be improved, limiting the number of simultaneous sounds that can be played usually helps a lot. Also gameplay-wise, i knew there was a huge ton of bugs behind my wall, which even less made me want to create a breach, as overlapping bugs can be very deadly since when you kill one, the body produced won't block the rest, meaning if there are enough of them you can not beat them all before they reach you.

Last thing : the player can only shoot again once the bullet touched something, it could give an interesting self balancing difficulty by making killing things far away more difficult since if you have the time to kill them while they're still far it means you are doing good, but it had another effect for me : i would barely kill any bugs while they're far and instead wait to spam them super fast once they get close, it makes destroying their bodies and the fungi much easier too. I think simply having a cooldown would be better.

Very good!