I've been playing the game for a while now and I can tell you that the difficulty scaling while playing multiplayer (same lvl as you are) is bullshit.
Though the singleplayer is playable it's not rewarding you at all at the end of the matches. So low xp and non-existent loot.
If you want to shoot at bulletsponges this is your game. The game also promotes pay2win way too much.
1/5 wouldn't recommend.
Don't even bother upgrading the Protestors, Crazy Ex-Employees or Construction Sites, AT ALL!
There will be plenty of stuff to keep you going without them. They'll just get annoying by the time where each launch takes a lot longer to finish.