I've read through all the posts here, and I'm well aware of balance issues on Cave and Jungle. I'm planning to lower the price to start up the generator in Cave stage, and I'm probably going to lower the chance of Trappers placing traps.
The Musca bug sucks, I thought I had fixed it in the past but it's still here. I will fix that soon.
Heya! Have to say, thus far its been pretty awesome playing through your game. Kind of reminds me a lot of a certain game I would play back on Armor games, started out as a survival sim/tower defense sort of thing, before eventually evolving into a full on survival shooter/sidescroller rpg sort of thing. Almost makes me feel oddly nostalgic.
That being said, the cave and the jungle are definitely the most difficult ones from what I've noticed thus far, and honestly don't need much more tweaks then probably those two to make them pretty playable up to round 20 or so. Just messing around I managed to get to 10 on the cave, though have to admit the strategy before lights come on is mostly to dodge/jump around like a chicken with its head cut off.
The trapper is definitely the single most annoying enemy in the game just with how many do wind up on the ground. They aren't TOO hard to notice when you're keeping an eye out, but between rounds i found myself getting snagged way more than I liked. If you could find a way to honestly just make them disappear at the start of a new round, or at the end of one, I'd be happy enough with that, but lowering how many they set down would work as well.
If theres any real general game suggestions I could give, it'd probably just come down to unlockables, possibly giving powerups for some of the tougher ones to get, or even perhaps allowing us to unlock a starting gun of our choice, though that would simply be quality of life options more than anything for me, and I wouldn't necessarily think it'd be good to give access to any gun in that regard. As much as I love using them as well, the submachineguns seem to be by and far the best guns in the game, with rifles coming up in second mostly thanks to some of the later/more expensive variants just dealing crazy damage.
All in all though, absolutely love the game. Haven't tried the space stage just yet, but between the shack, and the FER stage I'm absolutely in love with it. The mix of enemies in particular within the FER level is pretty great, and the fox animatronic definitely gave me some good spooks when it first showed up. All in all though, definitely look forward to more and keep up the great work, its honestly pretty inspiring!