There are three difficulty levels in the game: Chilled, Normal, and Serious (in order of difficulty). Each of them come with their own achievement for completing the campaign without dying. These achievements are not stackable. That is, defeating the Serious campaign will not automatically unlock the achievements for defeating the Normal campaign and the Chilled campaign. You will need to beat each of those campaigns separately. If this is your first time playing the game, I recommend you start with the Normal campaign. This will help identify your skill level (so you'll know what game speed to choose when you do the Serious campaign). I would save the Chilled campaign for pursuing other achievements such as Ship Hoarder, Ovoid, Robin Egg, and Right Stuff.
The differences between Chilled, Normal, and Serious are as you'd expect: Chilled has slightly shorter levels, enemies are fewer in number and easier to kill, and there are fewer projectiles to evade. If you've already beaten the campaigns on Normal and Serious, now is the time to beat it on Chilled--but with an eye on the achievements named above.
1. Selecting Difficulty:
Tap the screen to go to the menu where you can choose from Start Game, Leaderboards, Achievements, Help & Options, and Exit Game. Tap on Start Game and then choose Chilled.
2. Selecting Game Speed:
On the next screen you can choose your ships and your game speed in increments of 25: 25%, 50%, 75%, 100%, 125%, 150%, 175%, or 200%. Normal game speed is 100%, so choosing 50% means that the game literally runs at half speed. Choosing 200% means it runs at double speed. Thus, choosing a slower speed will be easier.
Assuming you are going for the Ship Hoarder (collect 30 ships) and Robin Egg (complete the campaign without losing a ship), I recommend 25-75%, depending on your skill level. If you choose 25% you should have no trouble beating the Chilled campaign and earning the Ship Hoarder and Robin Egg achievements if you are patient, and if you use the playing tips below. But beating the game will literally take twice as long as selecting 50%, so you might want to try 50% first.
If you're not going for any other achievements and just need to beat the Chilled campaign, I recommend 100-150%. You'll be able to fly through the game in about 15 minutes total at 150%). After you've selected, choose 'Launch Ships' and the game will begin.
Time to Completion
The length of time it takes you to beat the campaign is dependent on two things: 1) how quickly you kill enemies, particularly bosses, and 2) the game speed you select. There are 6 levels in the game. With a game speed of 25%, each level takes approximately 15 minutes to complete. So, if you choose 25% speed for this campaign it will take you about 75 minutes. If you choose 50% speed, you should finish in half that time (about 35-40 minutes), and so on. You will want to choose the fastest gameplay speed that you can without worrying about failing (because if you die during the campaign--i.e. you lose all your ships--the game is over and you have to start the campaign over). You can pause the campaign whenever you want by pressing the in-game pause button in the upper-right corner of the screen or the home button (Windows button on your phone). Whenever you re-enter the game, you will pick up where you left off.
Shoot 1Up is a unique shoot-em up game in several ways:
You don't collect extra lives so that when you die you use an extra life and resume play. Instead, you collect 1Ups that float around on the screen. If you collect them by dragging your ship on top of them, another ship will join your fleet. You can collect up to 30 ships! Each ship will expand your phalanx and make your weapon more powerful.
You should collect as many 1Ups as possible for two reasons. First, each ship is like an extra life so that if you get hit by enemy fire you lose a ship. That is, if you have 8 ships in your phalanx you can literally "die" by enemy fire 8 times before it's Game Over. Second, because they increase your fire power (spreading out your phalanx creates a powerful laser), it makes beating the game easier because you can destroy enemies faster.
Naturally, the game is designed to entice you to pursue the 1UP icons that float near the top of the screen. You should only pursue them when you're sure you won't get hit by enemy fire, thereby losing a ship in your phalanx and defeating the purpose of pursuing the 1UP icon (which will merely bring your phalanx back to where it was, rather than expand it). So, be patient and prudent.
Like the 1UP icons floating around, occasionally icons with the word Ghost on them will also appear. Collect them and a clone of your phalanx will appear on screen and mirror your movements. For instance, if you have a phalanx of 5 ships, another 5-ship phalanx will appear, doubling your weapon output! You still control only your original phalanx, with the ghost phalanx moving in opposite direction (i.e. if you move the original phalanx left, the ghost phalanx will go right). The Ghost phalanx cannot die by enemy fire, so you only have to worry about defending your original phalanx. Collecting Ghost icons, then, can greatly aid you, but, as with the 1UP icons, be careful only to go after them if you are sure you won't lose a ship in the process.
On each of the 6 levels you will be given a flight path decision. You can either keep flying straight, or you can temporarily bank right. Banking right is always harder (and, in fact, is it's own achievement), but it also comes with goodies such as pies (necessary for obtaining other achievements). I recommend you stay straight in the Serious campaign and save the pie eating for the Normal or Chilled campaign.
There will be a lot of enemy projectiles on screen at once. In most case you can shrink down your phalanx and maneuver through them (even if it seems like you can't). But, in some instances, it's not worth the risk and it's better to unleash your shield--your last-line of defense. Tapping on the screen will unleash a small explosion around your ship that will kill nearby enemies. However, doing so will also temporarily shut off your ability to shoot bullets and the phalanx-powered laser stream. So, that downside is something you need to keep in mind. After a few seconds, though, your guns will come back and your shield will regenerate. The shield is very powerful and I recommend using it when you get in a bind, or you can use it more often as a weapon for killing enemies (using your shield to kill 50 enemies in one level is itself an achievement in the game).
Shoot 1UP is an excellent shoot-em up game. The best on Windows Phone. It can be a bit of a bore, though, if you only play it on 25-50% difficulty level, so try to challenge yourself at higher difficulty levels and enjoy comparing scores with your friends in the leaderboards.