This is a rougelike game and the options you're given on a particular day are chosen from the pot. If you don't get the upgrades I'm recommending you may not necessarily need to restart if you can't re-roll for them.

Getting combos is obviously critical to earning upgrade points early and situating yourself for the end game.

Common combos to work towards at any point during the game include:

• Destroying aliens in formation while on approach
  
• Destroying the tiny 'Micro Fighters' at any point while on screen
  
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• Destroying Asteroids by breaking their chunks apart without nukes (including triggering enemy bombs)
  
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• Triggering enemy missiles in proximity to their owner to kill them (or other applicable alien types)
  
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• Destroying 15 or more aliens inside a single nuclear blast
  
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• Destroying descending entire polygonal formations of aliens (by any means)

Your most important goal is to build up the firepower of your main cannon and nuke production by the end of the first week.

During the first week, enemies move slower and have reduced health.
They attack slower, stay in formation for longer, and evade attacks poorly.

Asteroids fall slightly slower and break into fewer chunks making it easier to earn a combo on them. The same is true for polygon formations, which typically gyrate far less this early in the game.

Avoid using your nukes to earn additional points and preserve your stockpile for later waves.
Enemies and asteroids will rarely appear simultaneously, giving you a further advantage.

You should use your first upgrade points to buy the Nuclear Missile Lab and either Increase Production or Rationed Warheads.

Rationed Warheads will reduce the blast radius of your nukes by 50%, but trust me when I say you will come to appreciate quantity over size. This also has the same effect of bringing your production to 1 bomb per day. Purchase Increased Production if you don't already have it when it becomes available.

When you have finished starting your nuclear arsenal, aim for buying only cannon upgrades throughout the rest of the week.

Possible upgrades for your cannon at this point include:

• Increased Gimbal Speed - your angular rotation speed.
  
  
• Extended Magnetic Rails - increases bullet speed and damage
  
  
• Increased Fire Rate

I again ask you to consider the path of increased quantity by buying fire rate or damage first before gimbal speed. Remember that the aliens are still slow at this stage.

Avoid, if at all possible, installing Twin Shot. The reasoning, besides trading fire rate for increased bullet count, will be explained.

During the course of the first week, make an effort to have your shield destroyed by stray asteroid chunks, enemy bombs, or stray missiles. You will need to be un-shielded to unlock the Berserker upgrades path.

Week 2 ups the ante slowly until you're just about in the end game. You'll have to contend with multiple incoming projectiles at high speed, but once again I beseech you to reserve your nukes until there is no other option. Even at this point, it should be easy to stave off large missiles fired at the city, and in a few days, you're about to get some great upgrades to help you deal with the ceaseless nuclear threat.

If you've dropped your shield as planned and avoided upgrading anything other than the main cannon and your nuke production, then pretty soon you should be presented with the option of disbanding the city shield altogether via Beserker Charter.

Completing the Berserker challenge gives you two important upgrades: Tactical Nukes and Sawn-Off Barrels.

Sawn-Off Barrels further increases bullet speed and add a small amount of random spread to the cannon, acting like you have a stream of 2 bullets per shot instead of one. This will be very helpful for tracking incoming formations moving at faster speed, and also for evening out the spread of Ricocheting Rounds later in the game.

Tactical Nukes drops your total blast radius to one-quarter the original size - just bigger than the bombs launched by the aliens. However, your production and nuclear stockpile gain the maximum boost of 4x.

Having many nukes to launch will prove to be extremely advantageous with our final few upgrades in this week and the next.

When the option to build the Advanced Materials Lab comes up, take it, and when you are presented with the Cobalt Cannon, take it. The Cobalt Cannon upgrade maximizes your attack speed and damage to enemy shields and will synergize extremely well with Sawn-Off Barrels to provide good coverage and high firepower.

By now you've probably faced the Alien mothership and other enemies capable of launching those dreaded, spinning Roller Bombs. They can only be destroyed when caught in the blast of another explosion, and that means either having nukes in storage to launch, or good skill gathering multiple projectiles from the enemy to chain the blasts together.

Shooting these things just to keep them out of your airspace means wasting time not dealing damage to incoming enemies, many of which now capitalize on lightning-fast, high-density attacks to overwhelm your city.

Fortunately for you, you've spent a good amount of time building up nukes to use in a panic specifically for these occasions. Now you can watch as your single explosion lights up the atmosphere with the chained explosions of other bombs.

Of course, your most devastating weapon has yet to be displayed - Graphene Tipped Rods.

Available only after building the Advanced Materials Lab, Graphene Tipped Rods gives your cannon's bullets the ability to not only survive through the heat of a nuclear blast, but split into a random spread of super-heated buckshot upon exiting the fireball, turning your automatic cannon into an automatic shotgun.

Behold your Magnum Opus.

You've preserved the ability to distribute your immense firepower across the skies and keep a steady, healthy supply of nukes for whenever fate conspires against you.

So, while New New York cowers under its crumbling shield and fledgling bolts of static electricity, and while Greater London finally figures out upgrading all the way to the standard Buckshot actually decreases their offensive capability, Chicago 2.0 and its glorious, reflective bean stand resolute under burning skies and crackling pops of nuclear thunder - sparks flowing gently in the breeze.

From here on out, the fate of the city rests in your capable, calculating hands.

Fire nukes at a good distance to pepper formations with sparks of pure graphite, or even use them against ground-based targets such as missile launchers. Use your shrapnel powerhouse on Nullifiers to stop them from unleashing Anemone.

Keep those richer constituents alive as long as humanly possible!

Good luck!