[Steam] Zombie Army 4: Dead War (90% OFF / $4.99 - Historical low)

Can you not play the game without the DLC?

"Only" 7 are important ones, the rest are cosmetic crap as far as I can see. But they are 25€ while the game is 5 (or 4 who owns Left 4 Dead which I'm guessing are almost all of us).

Every season pass comes with a ton of customizations.

Season Pass 1 (which comes with the game for free), includes three missions and 24 cosmetics: https://steamdb.info/sub/689612/apps/
Season Pass 2 has three missions and 27 cosmetics: https://steamdb.info/sub/493347/apps/
Season Pass 3 includes the last 3 missions and 23 cosmetic packs. https://steamdb.info/sub/796042/

And the Ragnarok & Character set has the two Ragnarok missions and four player.

But they REFUSE to lower the price on the season passes past 50% off, and them not adding a complete the set option to get any missing DLC also sucks ass. Plus selling Ragnarok separately.

On the description of the Season 2 and 3 it doesn't say specifically what the the DLC gives to you, but seeing the price i'm confident to say that it gives at least the majority of the DLCs available, i'm just not sure about all of them.

And yeah, season 1 is free, don't forget to grab it if you purchase the base game.

No. As I said above: Getting the Season 2+3 passes gives you most of the cosmetics and the six normal missions; but you have to get the Ragnarok + Character Pack separately.

Sadly there isn't, the best option would be to buy the season 2 and 3 + Ragnarok DLC's if you want the full content.