OMG Thank you so much for playing and the thorough feedback! Yep totally agree with you on the sound front, definitely need to get a sound designer on our team!
Here's a spoiler for how to break the level 4 puzzle: First you need to pick up all the enemy computers that you can reach - that should be 4, and place them down in front of the track the really fast bullets are coming from, this will create a roughly equal stream of projectiles against the fast computer, and then you can just pocket and shoot back at it to defeat it!
Once the player realizes they can pick up enemies that kind of makes the game a bit of a cakewalk haha. We definitely will in the future try add a level selector as it would make some things like this easier to discover!