Today I got a sub 15 run on Level 3 and while cutting the video for upload I noticed how quickly I killed Cobrabot, it just took 20 milliseconds. So I watched the "fight" frame-by-frame and I noticed the boss died before I even pressed the attack button which can be seen on the input display. Here's a video of the frame-by-frame view and my theory that the attack might be "stored" somehow when entering the level while pressing attack. This is worth looking into more because 20 milliseconds is hell of a quick kill.