About the Ashfall mission, i didn't died till the last boss (3rd) encounter and i passed the invisible wall in the bridge but this mission is bugged. The character takes invisible damage from nowhere and dies, even if the character is away at some corner.

Was playing on a public game when i found this guy and i think that he is cheating with all these skill spams:

https://www.youtube.com/watch?v=x5LDyT79Xnc&feature=youtu.be

I wanted to play with other players and i joined a public game and my missions just got completed and i lost my progress...

EDIT

I havent played/cleared Ashfall and Oshara missions and to play them i have to pay 500k gold? Please fix the game, how can you release this kind of product?

First of all, that guy doesnt seem like cheating. he is just using projectile builds with gear that has "+1 projectiles" on it or something alike, which you can achieve by doing attended(?) runs (not sure, if they are still called like that tho). (bascially expeditions with the maximum number of modifiers, where the clear rank is based on time and deaths). however...

paying 500k gold for a mission of course is hard to achieve, but on the other hand by just playing the game you will get there with ease. just upgrade your endgame city, and then go for some tasks giving you gold. achieving 500k will probably take like 1-2 hours once you reached something like level 70 with your character.

as act 3 boss is also an ascended i appreciate having a hard time fighting the boss. the challenge feels great to me. if you die often, consider trying to setup a more tougher build, instead of damage. therefore the fight will take a bit longer, but its less frustrating, since you probably wont die.

About the missions i think that you missed the point, i am more complaining about the bug and not the gold. You see that missions are free to play at the first time, although my missions went all to "completed" when i joined a public game and i didn't had the chance to play them and check the story behind them. This is also a game breaking bug, your progress should't be affected by other players.

It has nothing to do with your build or damage i am talking about the bugs. There is a delay and you can't do something about it, you take damage from nowhere and potions are not working. In my first 2 attempts the Boss just left the map and it had about 5-10% health and i had to restart the game.
These bugs are game breaking and have to be fixed.