I don't think anyone is a fan of text tutorials LOL. I'll fix this problem in the next emergency update that will come today. (along with a boss fight map) Also, yes, you COULD just hold down a single 'Z' button while shooting. You only have to press 'A' once to enter aim mode, then press it again to exit.
That's not a bug, it's a feature. You get a fleeting 'invulnerable frame' after you get attacked, and you'll be able to walk through enemies to escape, in case you get cornered. Unfortunately, you can walk into walls during this frame too, which can be remedied by using 'Return' item to teleport back to where you started....but it's not in the game yet. I actually wrote this concept into the tutorial, but you probably (understandably) ditched it XD.
Thanks for playing and commenting!