Sure, you can just click around until the bottom falls out, but we could make it more efficiten.

You gave Upgrades, Inventory, Rooster Tales, Wardrobe, Black Market and Boss Raid. There's also a Treasure Chest you can get items for currency (called souls in the game), and a cauldron you can get easy souls.

Black Market is mostly a scam, as there are too many items in the game to use it reliably, and it also just loves to rob you from items you need to use the Raid feature.

The treasure Chest gives you items of certain quality you can even adjust. It's mostly useless, as you'll get your items primaly from the regular battles. In theory it has potential if you are doing Raids, as you can get one type of items from it (the ones you get 1 per beating a level, but this way you don't have to bother defeating the boss - but as the other ingredients are not available, it's kinda lacking still).

Raids: there are 4 levels to do Raids on. They provide items and wardrobe-items, and they are not just "beat the boss", but actualy the same as a regular battle-level, only harder. Items you need to do a run:
1: 30 Cheese + 1 Captain's Hook (you get both from the Octopussy-level)
2: 20 Green Scale (found in Deep Below) + 1 Moose Cheese (found in Borderland)
3: 20 Poker Chips + 1 Crystal Skull (both I think are from Royal Casino)
4: 20 Cogwheel + 1 Lucid Pill (both from Above the Sky)

Battle: this is the story-mode, where you get all kinds of items (inventory, wardrobes, souls). The First Siege still gives SOME item (of high level), but seemingly no wardrobe. The First Siege Hard is the endless mode, practicaly same as the normal level but harder. I'm not sure wether the items are of the same, or can be better (at least by stat).

Upgrades are your skills, they can be maxed out at character level 100. The prices go up to an insane amount (millions. I think the priciest item here is 10 million), but don't worry about that too much.
There is a resource and a Batlle tab, and incrising your Souls Cap should be a priority because of Rooster Tales.

Rooster Tales is ingame achievements. You know the drill: defeat X bosses, get Y amount of particular stats. The rewards can go to the million(s), so incrising your cap is adviseable, even though att he endgame you'll gain more souls than you can spend.

For weapons there are some categories worth mentioning:
- sniper rifles have the ability of "headshot", meaning the next time you fire in that direction, an enemy will be oneshot. Very cool feature, easily makes these items worth a couple level higher than their level.
- shotguns I THINK can/will damage both enemies if two are on the same side (not counting the campers at the edge of the screen)
- flametrowers are finicky, because you don't gget a clear feedback when they are causing damage. It seems despite their animatiion you actualy deal damage by normal clicking around.

The maximum amount of "money" you can accumlate is 100,000,000 souls. Not that you'd need / be able to spend it on anything at that point.

Now let's talk about the hardest part to 100%: the Wardrobe.
I decided to grind every map until everything falls out, and then move to the next area. I'll tell you how many runs I needed to do in each area for each item in the wardrobe.