What is the fastest way to level up each class?

[MacGruber]

I am trying to unlock the weapons but am not sure how to get the most XP to level up each class.

What is the best method to quickly level up?

[Fuccubus]

running highest but less challenging hazard level will be good for level up.

[Blurry Eyes]

In terms of time spent you just want the most OP builds and speedrun dive successfully.

In terms of level gain per run you rather want weapon builds that drag the run out. It has to have good enough damage to clear swarms and kill bosses but with weapons that don't target them down so you can kite as long as possible, mine as much of the map, kill as many normal bugs and collects as many xp gems as you can to get the most class XP per run.

Either way it's one of the grindiest aspects of the game you're best off just playing the way you enjoy most and level up in the process. I suppose you could just clear one stage then end the run quickly over and over again that might be time efficient as well though not good for unlocking other important things like overclocks.

[Metro]

Play normally trying to unlock the Hazard goals. Never felt I had to grind.

[MacGruber]

I only have two hazard goals left, 4 acid for which I need to get driller to level 24 to unlock the acid drone and get to lvl 60 with the 3rd spec of solider. I have not unlocked the 3rd spec yet.

[NathansWargamesYT]

I'd suggest hazard 2 after you got most guns open and ready to be overclocked. just keep running it

[Look]

you need for every levelup two finished runs, there is no progression in the levelup system. you can do this on hazard 1, its the same result as hazard 3.