Ok, lets start with the basic mechanics of the game. First, combat. Once you pick up the Contagion quickhack, combat becomes obsolete as you are able to take down whole areas without ever coming into actual combat, later quickhacking allows you to do this through walls so you no longer even have a LOS restriction. This horrifically unbalances the game as you cant lose, it doesnt matter how much higher in level than you they are, they cant defend against you launching a hack on them from extreme range through walls. If you choose to avoid hacking completely for this reason, it is still extremely difficult to lose unless you make a mistake and take out an environmental explosive at close range. I spent hours just punching mobs to try build up my skills, the size of the mob or their equipment level didnt matter, just went in with fists and only ever died when punching said explosives, the AI never troubled me. Second, content. There are a lot of open world activities like crimes to stop and random side jobs to do, like a whole lot of them. However there is very little actual difference between them, once you do them a few times you've done them everytime, particularly the street crimes where each one is almost exactly the same encounter each time, and the side jobs you can get have very little difference between them. Its a broad smear of very thin content, You are also expected to build up an absolutely vast fortune if you want all achievements though, as you will need huge sums of money to buy all of the vehicles, the vehicles which all handle virtually identically but even if you are to do every quest, every side mission, every open world activity, you are still going to have to spend a lot of time just grinding through crafting to make the money to buy them all as there just isnt enough otherwise if you intend on getting any of the higher tier implants. There is more, but alas, review post limits.
