The final level tends to restrict your movement more than the previous levels, and unless you watch carefully what's approaching it's very easy to put yourself in a situation where you're forced to take some serious damage. There are waves of some large ships you'll encounter fairly frequently through the level that have a wide spread of fire, and fire plasma cannons which will deplete your shields fairly rapidly (don't try to take all these out, just pick one ship out of each wave to try to pick off before it fires so you have a clear path to move through). The ships that also fire 6 missiles at a time are also very troublesome, as their movement patterns quickly pushes you towards the side of the screen if you try to avoid getting hit by them (try to move further up the screen and over these ships so you don't get stuck turtling at the side of the screen- that's a quick way to get seriously damaged on this level). Ground-based defenses are also much more troublesome than in any of the previous levels, with numerous missile banks restricting where you can move and tracking cannons set behind the missile banks making it much more difficult to take them out quickly (and these tracking cannons fire three shots at once, so it hurts a lot more if you just try to soak the damage). All of the missile banks are also hidden at first so they can be difficult to spot before they open up and start firing. These things taken together mean you need to be processing quite a bit more information than in previous levels when it comes to figuring out where to carve out a safe path for yourself. The final boss also requires more prioritization with much less room for error, otherwise you'll end up taking significant damage. Target the tracking cannons on the left and right near the bottom of the screen first, as these start shoot fairly early (it can be worthwhile to just soak some of the damage from them to take them out quickly). After those are gone target the large portion right in the center, as this contains numerous bothersome armaments. If you're quick in taking out the tracking cannons I mentioned then you can take out the central portion with it only being able to get off a few shots (as it opens up fairly late). You can also hit the central portion while moving to the very top of the screen, and when there only a single tracking cannon on the central portion will be able to hit you. Once you've taken on the central portion then there will only be forward-shooting armaments remaining which you can destroy at your leisure.