Having looked around for a guide to this game to no avail, I have decided to write a small guide to the game - While I've not yet completed it yet (been enjoying the dungeon diving far too much..still I'm 1st in A rank); I think I've got a handle on the various weapons and such to do with the game

First things first, lets discuss progression

See that countdown to having your organs sold? Ignore it to a degree - while it does have in game ramifications; you do not need to ace the game in the 30 days provided

As to those ramifcations...well..
>You lose all your earnings
>You lose ANY part not equipped before the Kami-1 (ie the last day - if you don't have rank c and 10m credits you need to organise your GEAR the day before)

Painful but it could be worse

>You keep any chips you gained (Thank Atsuga!)
>You keep your ranks
>You keep any code cancellers you gained (Keep a note of this)
>You keep all your repair kits
>You keep your upgrade XP
>You keep all the parts currently equipped to your GEAR

Now to progression

First things first, Rank determines how far you can go in the dungeons - You would think this means you should hit the arena as often as possible but thats a bad idea as you only get money and ranking points; your GEAR soon becoming extremely underpowered

From my experience the best way to go is:

Follow the game progression until you get to choose - if your GEAR looks capable (due to lucky dungeon drops) of Arena-ing do so otherwise hit the dungeons and go as far as you can until your GEAR looks capable of hitting rank C. When the arena closes, do the investigations (and don't forget to buy repairs!) - your aim is not to complete them (by all means if you can, do so), your aim is to collect parts. Go as far as you can but be aware if you die, you only get to select five drops to keep so being safe often is better than being greedy

In any case your aim is to avoid the RAGE floors (unless by some miracle you got an anti-atsuga weapon) and Intercepts - nothing or hangars is what you want as those two are the best and safest way to descend deeper. Every 10th floor is a miniboss room (9th floor is usually an escape) and those parts are often pretty good but only go that far if you think you can.

From here, do the investigations - in terms of rank difficulty, I'd say they are B/C- in difficulty so a few parts from it will make run 2 easier
When the arena returns - Ignore Namba, you won't get past 5 so fight the arena guy - In any case from now until day 0 go as far as you can in Arena mode (feel free to do more dungeon runs as you want)

On day 2 you now have to prepare for Groundhog day
>Build your best GEAR, sell the rest and either:
>Buy as many repairs as you can to resell next run
>Buy a code canceller (20m so a long shot but if you can, do so)
>If you have 10m in the bank, do a normal day then the kami the next (pointless as you won't get anywhere)

In any case you'll fail and you'll return to day 30 - now with a better GEAR, at least

For this and subsequent runs, use the time before the arena closes to rank up then Investigate - At least until you can clear the dungeon (ie floor 31) - If you can do that proceed to the B/A rank quests (or farm RAGEs in investigation as they'll easily do for B and up to floor 10 of A rank if you have a canceller to unlock them)

By now you should be able to get past stage 5 or Namba if not further so do so (each 5 stages has a bonus) if you want

Again, when on day 2 its time to tidy up your accounts - Set up your GEAR to take over, buy any cancellers or repairs then either try the kami or start run x+1

Repeat, dungeon dive, arena run, sell off and but take over items; repeat

So you did it; paid the loan and game over, right?

Wrong!

Now comes the ending stage..and boy, you want to make sure you have time to do it - its not too hard...just time consuming

Without spoilers - except bosses; deep dives and more bosses

It also introduces you to overkill (Lethal mode) weapons - Put simply, activating Lethal mode overloads the weapon for massive damage - However at a cost...once the Lethal gauge is spent; the weapon breaks and cannot be used normally or otherwise - Its a risk versus reward mechanic that is painfully easy to spam only to find your weapons all broken, turning the dive into a desperate search for an exit floor

Needless to say - save it only for the big bosses

Should you complete the final floor and its torments you are now free of the Groundhog day and you can continue to rank S in arena and in turn rank S in dungeon diving

This is the endgame where everything is turned up to 11 - RAGEs now prove terrifying enemies (even with Anti-Atsuka weapons) and (almost) everything is a horrendous bullet sponge

Enjoy!

Upgrades
Around a week into the run you'll get the rpg element of DGOO - Upgrades. Simply put, the more you have, the more skills you possess. While its stated its a permanent change, it only is for that run so don't be afraid to experiment. As one would expect the more powerful boosts require more upgrade points but in turn this reduces the amount available for other skills (well, until you lv 99 the thing). While it is advised not to fill one catagory above all others; it depends on your build - for example if you run an Overdrive and dual Pile bunkers (you madman, you), Investing in melee to its maximum will make for the most powerful option offensively

In any case, once a run is over the points are reset - until the upgrade machine is 'reinstalled' - at which point you can reassign them plus any gained in this run

Code Cancellers
Got any parts that are red in the menu? These are Atsuga parts and to unlock their skills you need code cancellers. At 20m a pop they are expensive but so worth it towards endgame. Ocassionally dropped from RAGEs they are best saved but often unlocking an investigation level Atsuga GEAR weapon can easily take to to the end of B rank before losing effectiveness

Chips
Coming in varied flavours, these are for the trade option in the shop - the traded parts changing with rank, hold on to them until A rank

Repairs
Unlike Tokyo, you don't have 99 of these per mission (which made the game hilariously easy apart from escort missions, bah) - instead you have 9 small, medium and large repairs (repair access being determined by rank) In any case if you are on a run and you want to 'port' money from one run to the other, buying repairs then reselling them the next run is a method you can use with an appreciable loss in return but considering everything is wiped when the run starts..

Also - if dungeon diving; if you have 99 stocked repairs of a type and get another; its simply absorbed for no return - and if you have less then 9 of a type in the dungeon and recieve on it will go to your current supply, not the stockpile

Due to the nature of the game, its hard to pin down an ideal build but the same applies to all

Evasion - You want this as high as possible. With this high enough, enemy shots will simply do nothing (which helps considering many guns make you stand still)

Las/physdef -If you do get hit, these values affect how much hp you lose

HP - Naturally the more hp the better but compared to the three above, its slightly less important

Speed - Nice to have to make moving around the dungeon faster but its not vital to have it as high as possible due to evasion in a movement and stat manner

Hit - Accuracy. Enemy accuracy 'attacks' the evasion stat - as does your accuracy to the enemies evasion abilities

LasAtk/Physatk - Your damage giving values. Higher is better naturally. Enemies can be weak to one type so that type will be more viable towards them

Sword - As one would expect, its a decent weapon; skills letting it perform multi hit combos

Pilebunkers - A personal favourite, the pilebunker in DGOO is weapon that balances its power with risk - it only has one hit per charge so missing or the enemy evading can be disastrous but in return if it does hit there is a tiny chance it can do 99,999 damage (if it has the one hit skill, of course) which is always a joy to see. A risky weapon to use versus fast GEARS/Rages due to the ability to miss but if it hits, they know about it.

Chainsaw - A great weapon..if you have the right skills. Quick turn makes its damage tick faster. Often I used it to apply status ailments as each tick of damage has a chance to apply the status. The best combo for a chainsaw is stun and quick turn - that way the enemy is stunlocked until they die


Handgun - Suprisingly good, you can keep moving while firing while its large ammo count and skills allow you to pepper the enemy with shots

Rifle - You need to stay still to fire but its damage is not too shabby and if it comes with a charge ability it can be quite powerful

Machinegun - Pretty mediocre, it allows you to move while firing. In my opinion its the 'jack of all trades' gun of DGOO - good, but not excellent

Shotgun - fires a wide spray of shots per trigger pull, naturally if point blank all shots hit one target. Piercing rounds have a good home on the shotgun allowing group destruction

Bazooka - Basically an explosive shotgun but beyond that... its pretty bad due to its reload rate, single shot nature and low damage for its nature.

Gattling Gun - What the machine gun and shotgun wishes they were. Huge ammo capacity, long range; it sprays everything in range. Its power to a degree its recoil will literally push you out a room if you stand by a gate (so if fighting bosses/RAGE do not spam it by the gate as their health restores if you leave the room!) Piercing ammo is great on it as is any recharge bonuses


Flamethrower - A versatile weapon, it sprays fire that weakens defence at 'meltdown' status. In early game its one of the strongest back options for crowd destruction. Luckily the enemy GEARS/Arena opponents seem to not realise the stream can be held

Landmine - Can be a fun little weapon in arena due to dumb AI melee - plant, scoot back; watch opponent run into it and repeat whilst twirling your imaginary moustache. As for dungeon diving...it can ruin a melee mob room groups day if you drop, return to safezone then return, drop and repeat until you have a pile then watch them try to get in weapon range

Missiles - Fires a number of homing missiles. If you can get a dual launcher with lots of extra missile skill levels this can be a good weapon for the back while dungeoneering due to splash and decent damage. In Arena firing a lot off will force the AI to run and evade so stunning them will allow all the missiles to hit - fast reload type skills allowing multiple volleys to be in play at once. A risk/reward weapon unless you lower their mobility via acid/stun

Laser - Fires a big old beam of energy. Capable of hitting across a room, its long; telegraphed startup is painful but if it strikes it can decimate a mob swarm - Added shock can ensure the mobs stay in the beam. Painful as an enemy weapon, even well timed evasive steps often gets you damaged - especially as many mobs fire it simultaneously

Focus Laser - Same as above but a narrower beam with higher damage in return

Satellite Laser - AoE laser. Stand in position, activate..a few seconds later a huge beam lances down and vaporises anything underneath. Has a radiating damage AoE so the closer to the beams core, the more damage. You WILL hate this weapon if an enemy has it in a group. Sustained beam is great on this as once deployed you can move away while it continues its beam

Grenades - launches explosives a set distance. Large AoE, big splash - requires a degree of practice to not fire it point blank as it will miss the mob at that range

Overdrive - Technically not a weapon, what it does is supercharges your GEAR, ramping up its stats for as long as it lasts while also boosting recharge times of weapons. Coming in several flavours that can accomodate different playstyles and weapon choices, if you get an OD-suffixed drop give it a shot

As to what I use, I tend to go Gattling/Pilebunker/Overdrive

My overdrive is speciallised to my recharge boost skilled pilebunker as this lets me rapid fire pilebunker shots on any nearby mob for one hit kills and immense damage. As to the gattling, its the other damage type to the pilebunker as this lets me approach most dungeon rooms like so:

Enter, unload gattling (if the enemy type suits it)
or
Enter, Overdrive (or overdrive then enter), unload gattling (against stronger types)
or
Overdrive, Pilebunker massacre

Needless to say there are no combinations that are truely unfeasible so don't be afraid to experiment but generally speaking you'll want a LAS weapon and a PHYS weapon on either arm to make the deeper levels of the dungeon less painful (or one of those rare 'both' type weapons...)

In any case, I hope this short guide helps navigate the Cosmopolis!