Yeah, I played it for a few hours and it's pretty nice. The scoring system makes the game.
The only thing I wish it had to be more like Cave is 1) I wish the gold would automatically come to you; having to go pick it up is annoying since like you said, your ship moves slow and you want to get moving to the other side to fight new enemies and 2) I wish your ship had more a more powerful screen filling width shot like in Cave games, which again would help with the slow moving wide screen ratio so you could still shoot down all the enemies.
Otherwise it's great and the replay value with all the bonus levels, and shop, and 0-5 star ranking system, and having to play on higher difficulties to progress; it's all great stuff that means I'll be playing it for 5x the amount I would be playing it otherwise. Definitely a good deal at $8.