Yup, thanks for the fix, looking much better. There's some other very minor issues, but if it's intending to be put in an arcade cabinet, it's not a problem.
Perhaps the buttons can come down in a manner similar to those guns that appear at the top of the screen for a second. They'd have a more spacy feel rather than a box.
Also you might want some label indicating how the player can find the information about different items, powerups, trophies, and so forth, at the main menu.
Otherwise, it seems pretty solid to me.
In regards to what you wanted to know...
The difficulty seemed fine, it allowed me to get through some levels, and then certainly got harder. I couldn't just pick the weapon powerup every time, I actually had to get the shield, and life if necessary, that's good. The game allows players to get better by playing the game more and understanding how the levels pan out, people will want to play it again. The high scores make sense. The trophies probably make sense, but I'm not going to achieve the others on a MAME scheme.