Thanks for the feedback! There are a couple of balance issues I probably need to look at. Would have been good if I got some variety in the bullet patterns too. What level did you get up to out of curiosity? If you get to the 5th level red enemies start coming (which require you to tag the bullets to red level), and the 10th has purple enemies I believe, with medium strength red ships.
The biggest problem was a bug I introduced in the last hour which makes you respawn in the middle at the start of each level, that's what's killed me more than the enemies itself :(
Anyway, thanks again for the play!