Zeroptian Invasion Walkthrough

2. General hints and tips

The game is very simple, with your ship only being able to move left and right, and firing a single bullet at a time. It is mostly just prioritizing dodging bullets over hitting enemies. However, you can make it a little bit easier on yourself by knowing the mechanics a bit and farming power ups.

  • You can only fire a single bullet a time and you can't fire the next one until your bullet either leaves the screen or hits an enemy. Therefore taking the time to shoot accurately means you'll actually be able to fire more often and kill things more quickly. That being said, avoiding bullets and just blindly firing is relatively effective while there are lots of enemies on the screen.
  • In general the game is more about pacing than quick reflexes. The speed you, the enemies, and bullets move at lends itself to slightly planning ahead and lining up shots.
  • When you start to thin out the enemies they will begin to move faster. When there is about 5 or so left you'll notice they move about twice as fast. When there is only 1 you'll notice they move even faster.
  • The enemies move left or right as a group and once they hit the edge of the screen they'll move down a row. You can make their path longer by killing the enemies on the outside of the formation first. A small group (or ideally a single column) will have to move across the entire screen before moving down.
  • There are three power-ups in the game: (P) power, which gives you two shots instead of one, (S) shields, which absorbs a single hit (essentially a free life), (=>) arrow, which makes you move faster. They're all obviously useful in their own way. Power-ups drop from a UFO which periodically spawns at the very top of the screen. Shoot it down and grab the power-up as it falls down. If you already have a particular power-up you'll get 500 points instead.
  • You can, and should, farm power-ups. To farm power-ups, simply kill most enemies on a level. In particular, I recommend getting them down to about 6 enemies so they're not moving faster and in a tight column so they take the longest to travel across the screen. You'll also want to kill the topmost row first in the first world since they fire diagonal projectiles aimed at your position. Then just avoid the group and its bullets until a UFO spawns, kill the UFO, and grab the power up. Repeat until you have all 3 power-ups.
  • You get a checkpoint after every boss. The first two bosses are on levels 3 and 7. Therefore if you lose all your lives after beating the first boss, so long as you continue you will start on level 4. You only really have to be able to beat a world at a time on your 2 lives. You can theoretically get all the achievements on a single playthrough, but you can also continue as many times as you want.
  • Most simple enemies are worth a 100 points. Most of the "advanced" (i.e., diagonal shooting/top row) enemies are worth 200 points. In the second world the enemies that take 2 hits to kill are worth 500 points if you kill them before clearing their columns (and sometimes you get 500 points regardless). In general, since you must clear a whole world on a single continue, you will get all the score based achievements in that go. So you do not and should not have to worry about your score really.
  • For beating a boss/clearing a world, you get an accuracy score bonus. This is purely your accuracy percentage * 100. So if your shots were 52% accurate, you will get a bonus 5200 to your score. This bonus, all the enemies in the world, and the boss guarantee you will get 10000 points minimum for beating a world. As this is the highest number of points required for an achievement, you don't need to worry about getting a good score. You only need to worry about beating the world.
  • You get an extra life at 10000 points. You're pretty much guaranteed to get this while clearing a world.
  • Big WARNING: if you let the enemies get all the way down to your level you'll die automatically! Don't let this happen. Kill the enemies before they get too low.
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