Loopy Game Play Modes
The Loopy is the fastest and most agile plane in the game, but at the cost of very low health. The primary fire weapon in all of the available game play modes are tracking missiles, which are unique to the Loopy. The combination of speed and powerful missiles makes this plane a good opportunist; able to quickly enter combat with an enemy and leave just as fast if the situation turns for the worse.
The three main game play modes, or Red Perks, are Tracker, Double FIre, and Acid Bomb. Each game play mode gives the Loopy a characteristic allowing the user unique ways to approach battle with enemy planes. It is important to remember that, while each game play mode offers advantages and disadvantages, none of the game play modes is designed to be better than any other, but rather each just change the way the Loopy is played. Experimenting with each mode will give you the best feel for which mode works best for you in different situations.
The first of the three loopy red perks (and the first red perk that you receive in the game) is Tracker. The Tracker mode's primary weapon is a single fire tracking missile, and its secondary weapon is an exploding EMP shell. The Loopy single fire tracking missile has greater tracking flexibility than the double fire, but since the missile fire one at a time it deals it out more slowly. The Tracker requires the Loopy to lock on to the enemy for it to begin tracking the plane. This enables Loopy users to implement a fire-then-lock approach to their attack, instead of the usual lock-then-fire attack. This perk does relatively low damage, but is ideal for beginners to start out with as you don't have to worry much about aiming. Most players discard this perk for the better burst damage of Double Fire, but it is used occasionally by better players.
This is the second of three game play modes that is unlocked through leveling. The Double Fire mode is similar to the Tracker, except that every press of the primary-weapon key results in two tracker missiles being fired instead of one. Doublefire tracks negligibly less than tracker, but does much, much higher damage. It also consumes a bit more energy than Tracker does, so you'll have to be more careful with your energy management. This basically means that you should discard tracker in favor of either Doublefire or Acid as soon as you can. For the number-oriented, tracker does around 150 damage/second, whereas Doublefire and Acid both do 240 damage/second. Doublefire also frontloads damage better than both Acid and Tracker, making for a more "bursty" playstyle. Having EMP makes Doublefire the best Loopy perk for dogfighting, as once you get an EMP off, you can easily outmaneuver your enemy from there on out. EMP also makes Doublefire extremely good in TBDs, as slowing down bombcarriers/escorts will make defending your base a much, much easier task. It is also considerably easier to get used to than Acid, and offers the same DPS, so this is the recommended perk for beginners(after Tracker has been left behind).
This is the third, and final, of the three game play modes that is unlocked through leveling. The Acid Bomb is a green explosion of acid that is fired instead of the usual EMP as a secondary weapon. Planes that come into contact with the Acid Bomb will be temporarily affected and will continue to lose small amounts of health, as well as take 33% increased damage until the effects wear off. The main thing to note about Acid is that you absolutely need to get enemies Acid'ed before you start firing on them(assuming a full health enemy), because the primary of Acid is basically the same as Tracker(very low DPS). Acid is mainly used for support as it is extremely good in teamfights(imagine the ideal situation - getting 5 enemies with 33% increased damage taken, it's a gamebreaker). It can also be effectively used as map control in chokes together with bombers/explodets. For the numbercrunchers out there, Acid does the same DPS as Doublefire - 240 DPS, assuming Acid is on the plane. Without Acid, it does 150 DPS. The DoT portion of Acid takes about 40/35% of the Mirandas and the Loopys health off, so as you can imagine you'll be getting quite a few off-screen kills.