BlackSpy said:
There are a few things I don't really understand though, are the homing shots more powerful enough that even if you are looking right at your target your best to use them?
What's the little gauge in the bottom right about?
Why can I never see the goddamn enemy bullets?
Normal shot vs. homing missiles -
As a rule of thumb, the normal shot is good against larger, slower enemies and narrow formations of small ships, while the homing missiles are best used against swarming formations that otherwise would surround your ship and force you to use the Break Laser to save your life.
However, sometimes you may want a larger enemy to linger around for a while in order to get a larger bullet spray for a Break Laser bullet bonus, here it's best to use missiles to keep smaller enemy ships at bay while you wait for the bullets to come in.
Gauge at the bottom right -
This is your level score goal gauge, it increases proportional to your normal score and bullet bonus and lets you border-up if the goal is met. This is the core of the gameplay - choose the border that fits you best and border-up after you've reached the level score goal. Some yellow or red borders may be easier to beat for you than the green one, for ex. I find red-2 a lot simpler than green or yellow, but since the borders also determine the number of ships left, it's dangerous to select red border if you don't know it very well or won't reach the score goal.
Some lower borders also give you more scoring/bonus opportunities than the green one, just think of the giant mining drill-like sub boss in the 2nd part of level 1, it spits more bullets when being shot at than in green or yellow border (more bullets = higher bullet bonus = easier to reach level score goal).
Also note there are several ways to milk the bosses for bullet bonus score (see the vids that come with the game for example, the second one of each level/border has the scoring tips), but it's equally important to kill the boss in time, otherwise your score will be much lower.
There are a lot of single zig-zag bullets flying around in many levels, as well as suicide bullets of destroyed enemy ships, these can be particularly nasty in the vertical scrolling parts in level2.
Oh, and BD has a ship speed option, so use it. Most ppl play the game with speed fixed to 75%, but that's not the best choice for flying through narrow passages. Some bosses (3, 4) and sub-bosses (1, 4) are easier to beat with good speed management.