Receive gold on all simulation discs. A lot of people have had trouble on this but it’s extremely easy if you listen to what I say.
First, you want to collect every single disc on easy difficulty. If you do that, you’ll take less damage, the bosses will have less HP, and the enemies will be easier.
Second, when you’re doing these make sure you kill everyone as fast as you can. I recommend beating the game first so your guys are around level 30-35 so you have really good moves maxed out. Do not leave any person alive. If it is an unlimited spawn, don’t destroy the objective until you have reached 5,000 from your point goal or you’ve reached your point goal. With 20 minutes, you have nothing but time. You should never be short on time.
Lastly, organize your characters as soon as you get into the game. See which moves are best and how they will help you. Utilize certain areas of levels and take advantage of it. If you see someone running around with a weapon, steal it as it’ll make killing a lot faster.

Follow my tips and you should do really well. I did them all on my first or second try.

Won 100 arcade mode levels – This is actually really easy if you do it right. What you need is 2 controls first. Go to Act 1 Wrenchworks from your S.H.I.E.L.D access point. Use Ms. Marvel and Invisible woman and get to the very end of the level. Skip all the guys and just get to the very end. Right before you exit the level, load up the second controller and put it on arcade mode. Use Ms. Marvels ranged move and kill a few guys with the first player controller. Usually 2-4 is fine. Once you’ve done that, exit to the omega exterior and there’s your first arcade win. Rinse and repeat and you should be done in no time. I don’t have this achievement yet and the only people who I know who have it don’t know if you can turn off your console and continue. So please be careful when you do this because if your 360 stalls like mine did (at 40 arcade wins), you might have to restart all over again from 0.
It should take around 30-60 seconds per arcade win.

Tron Edit: You ARE able to turn off your xbox and continue later. Either the next day or four months from now.

There’s 2 ways you can do this:

1) You find 3 other people to play online with you
OR
2) You’ll need 4 controllers for this. Play through normally and when you get to the final exit of a level, hook up the rest of the controllers and play on co-op. Finish the level with all of them hooked up and then when you’re done disconnect them all. Go to the next level and repeat.

If you go to Stark Tower (Act 1), and keep going into Iron Man's lab, and then back into Stark Tower, that counts as a level. Doing this, you can get the achievement in less than 10 minutes. You will also get "I have a friend", "Super Hero Team", and "Teamwork" if you have not gotten them already.

Just use invisible woman or Black Panther to beat the cityscape level without defeating and enemy and there you go achievement unlocked.

Alternative method:

Instead of trying to avoid everybody and rushing through the level, just play it normally. At the end of cityscape go to the next area, then re-enter cityscape and go into the next area. That way the counter resets itself and it appears as though you went through cityscape without killing anybody.