Absolutely awesome!
At first glance the game gave me a factorio type of vibe, but the way it's set up makes it so resource management isn't really a problem (I was able to very easily beat every level with just repeaters, splitters, and side projectors) so it's pretty chill. I really loved the game's concept, and its sound effects and music do a very good job of really selling the execution. The soundtrack could use a bit more variation, but it's not really much of an issue since the current song is pretty good.
I found a few glitches: There's the shooting-through-blocks glitch that you already know about, though if I'm being honest that glitch isn't game-breaking so I'm not sure if you'd even need to remove it since it could be used to add a bit of strategy to things. (Imagine a level that bans the piercer and wants you to figure out a way to get through some walls. You could use the glitch, or you might rotate the edge blocks to form a tiiiny path way if the corners are missing.)
There's another glitch though: amplifiers and piercers don't seem to refund your money when you sell them. Or, at the very least, they don't refund all of the money you spent on them unless they're at the default price. Normally it's not a problem but... I'll come back to this later.
I also found the piercer to be too OP. It can pass through everything—walls, gold blocks, void, and I think even the wrong side of redirectors—with absolutely no limit to it other than how many redirectors you can place. I agree with LipeCarmel that you only really need one, but they only cost 300... the lack of sound effects when pierced objects fly through something also makes it feel worse to use than the fun bouncy balls that you start with. I kind of feel that it should have a max pierce limit, or maybe make it so the bullets don't keep their pierced property when they enter a redirector.
I really love the fact that you took the time to make so many variables in the game customizable, though! I personally am a fan of RTS-like strategy games so I managed to make a custom pre-set special challenge that puts you under a good deal of pressure, but is still 100% possible. I know LipeCarmel mentoined the game could use a more challenging aspect to it so... hopefully this helps!
It forces you to scout by buying and selling in the fog, plan ahead a bit, and figure out what you want to save for early on. Voids grow faster. Repeaters are less powerful but their low price makes them feel a lot more useful. They aren't enough on their own, though, and resources are somewhat limited... but there's still enough to work with. You also get rewarded for being fast because the faster you work, the less of the map gets destroyed. It's really interesting and fun to play!
This is also where the amplifier/piercer no-refund glitch is so detrimental, though. When you spend like 6k on a piercer or 8k on finally getting an amplifier and then sell them, you lose the HUGE amount that you invested in them for their power. (I'm also considering reducing the piercer to 5k.)
I also found out about another really fun concept: beating a game without a single repeater. I did it by starting a game with a void right next to my starting repeater and then didn't buy another. Instead of a repeater I used a redirector loop with a splitter, so it's more limited and you can't just sell and place it wherever you want—You have to work with where the first loop is. Really fun!
Sorry if my comment is too long. When I write comments/review for games, I tend to be wordy, and I'm even more wordy with the games that I like the most!
This game is amazing, and I'm really looking forward to seeing what you do with it. Thank ye for all the work you've put into it!☺