The progression is insanely difficult. You are practically relying on getting the bonus presents for 4k, otherwise you will be stuck for a long time clicking. Not fun
It's not hard. It's just grindy. Get 1 or 2 lives, spend the rest on reload speed and movement speed. Weapon upgrades - max dmg and spread, 1 pen, 1 rate of fire and 2 mags
Yes, thats the fun! You accumulate progress between server restarts and with every next restart you are a bit stronger and start at the same time as everyone else, can catch up fast and try other skill tree.
the hard badge is easy - just throw your weapon at the enemy that you want to kill, keep doing that and you will have a few pistols at your disposal that you can perma stun other shooters as well.
if you came here for the easy badge and haven't played the game before.. Don't even bother. You won't be getting it. It's a wild grind to get level 8. (Mentioned in other comments as well)
if you want to be efficient - when moving on to the next level(defeating the boss) pick a few good recipes (like armor, necklace, ring, shield), purchase the upgrades and let them grind while you are not playing. you will come back to purples that you can equip and desynth which will speed up your gameplay.
2 days of progress after pressing save? I pressed "save" and went to sleep. In the morning I boot up my PC and it start from scratch. This game is a disgrace.
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Yes, thats the fun! You accumulate progress between server restarts and with every next restart you are a bit stronger and start at the same time as everyone else, can catch up fast and try other skill tree.