Yeah I did the same and it quickly became very boring as I just held down the x button. This issue is largely due to the bounding box set on the sprite being far too small. As long as you avoid a bullet through the center of the sprite, it doesn't register as a collision... There will need to be some tuning as well as without the safe zone, it would take far too long to defeat the boss. All in all though, pretty decent considering it was made using construct 2...

Having a very small (even one pixel) hit box for the player is actually sort of a tradition for this kind of game: http://www.significant-bits.com/the-1-pixel-collision-box

Having a safe zone in a boss fight is an issue though.

Can you suggest some of the old coin-ops of the same genre? I remember having lots of fun with many but can't, for the life of me, remember any of their names. All that comes to mind is Ikaruga, but that was on the GameCube or whatnot.

Yeah, Ikaruga was a classic. For very traditional "bullet hell" stuff, I recommend you start with the Touhou Project (a million games, all of them are essentially the same thing). I've also been playing a lot of Jamestown lately. Unfortunately, I'm running on very little sleep and nothing is else to coming to mind, but definitely check those out.

Ah, thank you. I'm not looking so much for bullet hell stuff, there were less bullets than this, but I remember ground vehicles you could destroy, nice graphics (maybe on the Neo Geo?), powerups, things like that. It was a military installation-themed thing...