Extra chaos was my favorite mode! But it comes with a paradox as it's a bit more easy to survive by just turning on yourself. The idea of the big overload growing is nice but it's masking one part of the screen that could lead to some frustration, I don't know if it was intended :)
In normal mode, you can't shoot directly after an overload on the opposite as the chaos mode.
The art made me think about binding of isaac, super meatboy, that's well known code and that works perfectly with you mechanics and ambiance :)
A tips here, if you don't know, is that you can use .toString("00") to display 2 digits (for your timer) even if the current time is 3 sec.
I would've like to see my final timer btw once the game is over! That said, it was fun to have a couple of run :p Congrats!