It's great to be able to review something right after another entry in the series! I believe this was in fact better. It wasn't as much of a problem with how you had to power up that one weapon. You get easier weapons right at the beginning. While I'm still not sure of the actual limits of this, I appreciate the whole thing. The music is even better.
I don't think the original one had sound effects. These work much better. Even the way the enemies explode is cooler. 1.5 is kind of a weird title. I guess it's just because it's that similar to the first game, but still better.