Can you level up in Classic using only idle? And if so, whats the most possible?

Yes, you can. Look at rafflebot. He levelled up just from birthdays.
That being said, if Warzone lasts long enough, any level is achievable via birthdays.
Even though the game will probably rename itself.

idle gives:

2000 xp for beating a level once
2000 xp for getting all techs on a level
so 4000 xp * 28 levels with achievements = 112k xp for beating all the levels once

2500 xp * 7 achievements for the Arenas = 17,5 k xp for the arenas

Then there are a lot more of individual achievements that are 3500 xp (inspire X mercs, achieve army income of X, craft an item worth X, acquire artifact of rarity X ), of which there are about 24, total = 84k xp

2000 xp for finishing an idle battle, 3500 for finishing an idle battle first

4 for WZI BP, for i guess 2000 xp (total 8k xp)
4 for the challenges, 2000xp a piece = 8k
4 for daily bonus, 200xp a piece = 8k

2 for completing all the levels 2 or 3 times, total about 8k

Grand total = 251k xp (level 21)

Edited 4/5/2021 21:53:45

Need to define "level up".

Can you raise your level a few notches? Yes.

Can you get to level 60? No.

The only way to gain levels while playing Idle (assuming no Arenas) is via Achievements. I don't think birthday achievements go past 2 or 3 years in; I certainly got no points for my Fifth Birthday.

So you just need to add up the points for all the Achievements you can get without playing Classic and see what level that gets you to.

EDIT: I see JK already did that. Going by levels then, Idle alone can get you to level 21 and almost 22 (https://www.warzone.com/wiki/Levels).

Edited 4/5/2021 21:54:24

@Kynte Hey I remember playing you on many occasions, you are the chess guy who says hi! gl; hf

Idle has arenas, which never run out, so an idle player can reach any level by winning at the arena.

Note that, officially, the concept of points and levels don't exist within the idle apps. Your level is not shown to you, and you are never notified of receiving points or levels. This is because all the rewards from leveling up are things that only apply to Warzone Classic, not Idle, so it wouldn't make sense to show them as unlocking things they can't use.

However, players still get points and levels as normal even if they only play the idle app. If someone plays idle for a while and then switches, they'll likely get a barrage of level ups.

lol, I just imagined someone's device crashing because of the lvl ups.

Note that, officially, the concept of points and levels don't exist within the idle apps.

But they could apply . . .

They could be used to unlock things like additional artifact slots! (;