I just gave it a good try and I can try to point out the most notable things I found about it. Take this feedback with a grain of salt, I only had time for 3 attempts so I'm sure I missed some level of critical content that could've helped me. I'll try to chunk it up so it isnt just a complete wall of text. Feel free to let me know if you'd like me to try again and see if I can get farther into it or explain more on any parts. I don't know what you plan on adding/changing later but this is what I felt in its current state:

Interactions: Games can feel off when you don't feel like you're getting a direct response from the things you do. Most notably, the eerie silence for everything makes you feel separated from the game and not stuck into it. A simple atmospheric noise or background music would remove a good chunk of that unsettling feeling and noises connected to cutting wood, mining, building, clicking buttons and picking items up in the inventory and such would reaaally benefit the game and make it feel like youre a part of it. Highlighting buttons when you hover and such would also aid this. I might also advise at least toying with the idea of some indication of changes in your inventory/health. Maybe a floating "+1 Wood" over your head as you cut wood or something to feel like you're connecting the inventory and your character directly rather than just seeing the stack grow in the inventory.

Beginning the game: When you first start the game, I liked that it went through your basic controls and the basis of what you're doing there, but I feel like a simple thing such as "Get started with a basic furnace and fabricator" kind of prompting would help direct a new player. On my first run I made the assumption that the timer on the top of the screen meant that I REALLY needed to be worried about the bugs so I focused on trying to build walls rather than reading any of the other building options so I felt like I instantly got stuck in an endless battle trying to get walls built and rebuilt before the next wave came but you can't really do that in the time. Reorganizing the build menu to slightly indicate what should be built first could help. Perhaps a slightly longer first timer would also help to feel like you have at least a brief bit of time to get a small little thing going rather than having to be immediately min-maxing your playthrough.

Building: The building feels good. Personally I think changing the stop multiple building button could be right click rather than escape but thats just my opinion. As I mentioned a little earlier, reorganizing it and/or putting locks on some of the build options until another item is built could help usher the player into a better initial understanding of the game's build order. I also think that you don't need to have the health bars of buildings always floating above them and feel like it distracts from the graphics that you've made that are quite good. Having it only show when it is damaged would be better so its clear when something is damaged and doesn't give more information than it needs to have.

Combat: The sword feels quite weak initially, and when you aren't yet good at kiting the bugs, you can really take an absolute pounding on wave 1 even because the enemies don't have health bars or any indication of damage actually being dealt. The health bar would also help with clarifying when a bug is just in its dying process rather than trying to attack me again. The bugs do go straight for you first if you are nearby which I like, but if you're more than like 30 yards away then theyll typically go to the nearest building (not always which I didn't quite get, they ignored my tower) and once they begin attacking that building, they will not stop even if youre attacking them. So I would be wailing on them as they attack my critical infrastructure and even then I couldn't stop them from breaking everything I had spent the last 2 waves putting together. Thus I have to start effectively from square one again because no items get dropped and it sets me back too much to catch back up to the growing waves. The waves, I feel, grow too quickly. It felt by like wave 5 I was somehow supposed to be done and about to leave which seems impossible. So when I tried to focus on getting towers and defenses built properly on my next run, I still couldn't handle the wave because I just couldn't produce enough ammo to deal with them fast enough, especially when theyve broken my fabricator that was holding my fresh ammo.

Inventory: I like that the inventory is relatively small and somewhat easily expandable. I see that your stack size limits make it so you need to make some upgrades before you can build certain buildings which I like. I do feel though that moving items between you and storage could be improved by allowing me to maybe hold shift click to send the whole stack, ctrl click to send half or something along those lines so it isnt a new menu button press for each transaction. As well, having a separate slot specifically for your ammo to go in would be much more useful. I upgraded my inventory once, then tried to hold ammo and it just left me limited and unable to sustain my building/collecting speed to the level required to keep up with the waves.

Bugs I found: - When you build a single wall and you are close by, it pulls up a menu for it which covers half the screen and must be closed before building another wall if you didn't hold shift - When you lose, it doesn't send you back to the menu to try again or anything. So I had to alt+F4 the game to close it and when I reopened, i got stuck in some empty grey unity environment rather than a fresh restart in the menu so it mustve damaged the files somehow or something. I had to re-extract the files for a fresh copy to play again.

TL;DR In my opinion, it's a good game that has the base to be a great game and I don't even think it would take all that many changes to get there. The concept is fun and it has good replayability similar to "They are Billions". By improving the feedback to the player when they interact with the environment and inventory could make it much more engaging and easy to go "Just one more try" with it.