You're going to need all the help you can get, so I'll throw in some advice for taking down this monster achievement.
To reach Ultimo, you have to finish all 6 Tony Stark missions and all 6 Iron Man missions. Then, hit the three center tiles to open the mission sinkhole. Let's get started.
Kickbacks are vital on this table. They must always be lit. If they're not lit, they're your first priority. Get them lit immediately. I found it best to use the Stock ramp and the Party ramp to get the ball calmly down the inlanes. Don't forget to switch the lit inlanes with your flipper buttons. If you drain, your kickbacks are gone, so get them back right away. Your multiplier also goes back to zero, so working on an extra ball on this table is tough, as getting to x10 is the only way for an extra ball.
There's also a calm drop from the slingshot (top left flipper) down to the right flipper if you just hold the slingshot out. This calm drop can help often during missions. If it's coming too fast, you can send it around the loop to slow it down, or just let it fall fast. It will still land somewhere down near the right flipper.
Again, there's only one way to get an extra ball on this table, and it's kind of brutal. You need to get your multiplier to x10 using the lanes up top. You can switch the lit lanes with your flipper buttons. This is difficult because there's no good way to actually get the ball up there aside from the initial plunger shot and during the Mandarin Electro Blast mission. Good luck with those. I never tried hard for the extra ball.
First, I always went after the Iron Man missions. I didn't even look at the Tony Stark missions until all Iron Man missions were complete. By the time you finish up the Iron Man missions, you'll have some of the Tony Stark missions completed through natural shots anyway. I'm going to go over the missions and their difficulty. Because Iron Man missions are random, you might think explaining difficulty doesn't matter, but it does, as it affects whether or not you should start over when you drain. If I've got the two hardest Iron Man missions done and nothing else, then drain, I'm playing out that game no matter what. If I get two easy Iron Man missions done and a Tony Stark mission done and drain, I'll probably just start over.
Iron Man missions
Mandarin Flame Blast
I once failed the first part of this mission NINE TIMES STRAIGHT. The first section gives you 20 seconds to hit each center tile. When you hit a tile, the 20 second timer resets.
I suggest slowing way down and aiming carefully at the tiles. If you happen to go up the Stark Tower ramp, you've lost about 6-8 seconds right away. Don't panic and make calm shots by trapping the ball on your flippers and using a fairly quick release-and-shoot to hit the tiles. One last shot into the mission hole after that.
The second part isn't nearly as challenging. You can just shoot the ball out straight into the lit sinkholes using the flipper buttons. For the far left hole, wait until the right cannon touches all the way left and starts moving right. Then shoot. For the next one, wait until the right cannon is in the middle of its cycle. For the next one, wait until the right cannon touches all the way right and starts moving left, then shoot.
For the next hole, wait until the left cannon goes all the way left and starts moving right, then shoot. For the final hole all the way on the right, wait until the left cannon goes all the way right and starts moving left, then shoot. If you miss at any time, you'll have to manually get the ball in the hole. This isn't too hard, but the entire table is essentially cut in half. Make sure those kickbacks are on!
Mandarin Impact Beam
You need to hit every ramp and orbit once. You have 90 seconds, which is more than enough time. Then you must hit the ball into the mission sinkhole. This is all very straightforward. You should be comfortable with all the ramps and orbits after practicing a bit. The best way to reach the Science loop is either a drop from the Stark Tower ramp or coming around from the right orbit. Knock this out and let's move on.
Whiplash is like the whipping boy on this table. He never presents any challenge. You'll have to hit 6 ramps and orbits that are lit. The three lit ramps/orbits alternate every 10 seconds. The Science loop is never lit.
Whiplash will crack his whip on the playfield. Occasionally, he might hit your ball. This really doesn't affect the mission in any way. Your ball just disappears and another one auto-launches.
Note that after this mission "ends," there is, oddly, about a five second period of animation where the entire table is essentially turned off. You can still drain, though! Try to be safe or just trap the ball during these five seconds.
Mandarin Vortex Beam
This is very similar to a wizard mode. You'll have a ball save active for 10 seconds or so, and we're going to abuse it. When the 4-ball multiball starts, LET THEM ALL DRAIN. The hardest part of this mission is hitting the Science loop. Letting the balls drain causes them to auto-launch due to the ball save being active. Quickly knock one through the Science loop. You'll have four fairly easy shots at it. After that, you'll need to hit all the ramps/orbits once. Then, you need to sink the remaining balls into the mission sinkhole, which is occasionally covered by a vortex that sends the balls wide. I never found the vortex dangerous. You can even get a hard shot straight through it.
You're supposed to get at least 2 balls into the mission sinkhole, but I've seen weird things happen if you don't get them all in. I've seen the game actually glitch to where the tiles move back up and block the sinkhole right in the middle of the mission. No fun. Because of this, it may actually be easier to do this with just two balls, so you may consider letting a couple drain. Once you're down to one ball, just carefully take your time and hit it in the mission sinkhole.
Mandarin Electro Blast
You need to hit the left orbit, the Stark Tower ramp, and the Science loop. You should be familiar with how to do these by now.
After this, you'll need to get the ball down to the right flipper. Remember, an easy way to do this is to hold your left flipper button down when the ball is up top so that it carefully drops down off the slingshot and down to your right flipper. Then, back up the left orbit. You can use this time to alternate the lit lanes up top to try and raise your multiplier. If you can get it to x10, an extra ball awaits you in the Science loop. Whenever the ball is coming back down, just hold the slingshot out and left it fall down to your right flipper and repeat. It takes about four total shots up the left orbit. This must all be done in 60 seconds.
Whiplash & Mandarin
First, you'll need to hit the left orbit, right orbit, and Science loop.
Then, the Stock and Party ramps turn into sinkholes which load the cannon. When aiming the cannon, you want the top of the cannon lined up with the bullseye. That's easy to do with the top two shots since you can get them while the cannon is rising. For the feet shot, just let the cannon go all the way down and as soon as it starts to come up, fire.
Overall, this mission isn't too hard.
Tony Stark missions
Hit the Stock Market ramp a total of about 10 times.
Hit the Stark Tower ramp a total of about 10 times.
Hit the Science loop a total of about 10 times. It's actually not too hard to do this all at once, since the loop sends the ball right back at the slingshot.
Hit the Party ramp a total of about 10 times.
Shield Target Practice
Hit each orbit 6 times. After that, hit the ball up the Stark Tower ramp. You'll be taken to a mini-game where you must shoot down all the targets in a certain amount of time. I never found this difficult, as the cannons have red lasers aiming out of them. Don't forget to hit the targets on the sides.
Knock down the two targets in front of the Lock sinkhole on the bottom right of the table. This is not a tricky shot, but it can be a dangerous one, as the ball can violently come right back at you after hitting a target. After the two targets are down, lock the ball by dropping it into the sinkhole. Repeat this two more times. You'll then be "rewarded" with a multiball mode. I literally just put the controller down for a few seconds. I don't care about the points, and this mode tends to attack your kickbacks. Once the ball save is gone, let two drain and get back to work.
Wizard mode. Brutally difficult.
You'll be given a short ball save - maybe 10 seconds. Four balls auto-launch, Ultimo rises from the center of the table, and here we go.
Three ramps at a time will light up for about 10 seconds, much like the Whiplash Attack Iron Man mission. If you get a ball up a lit ramp, it catches fire. Balls on fire can hurt the big bastard in the middle. Do your best to hit him with the fireballs. You can hit him multiple times with one fireball. Hit him 10 times with fireballs, and you win.
You're going to lose balls. It would be nearly impossible to defeat Ultimo with all four balls still on the table. You HAVE to keep at least two balls on the table for wizard mode to stay active. Aim at the ramps using your peripheral vision while keeping balls on the table. If you get one on fire, start shooting toward the middle of the table.
Ultimo is huge and takes up a big chunk of the table. He also has some offensive attacks that will send your balls flying. You need to ignore all of this. Pretend he's not even on the table unless you're shooting a fireball at him. Aim your shots wide. Really try to see where the lit ramps are! It will be difficult, but try not to get distracted by Ultimo. The only attention of yours he'll be getting is when you have a fireball for his face.
When you drop down to two balls, start slowing down. Don't be afraid to trap a ball to slow things down further and catch your breath. Four balls with a giant robot in the middle will wreak havoc on your kickbacks. I actually had to use a bangback to get a draining next-to-last ball back on the table for the win.
If you drop to one ball, you'll have to start alllllll the way back over. You're probably going to need plenty of practice. If you get frustrated, walk away and come back later. Playing angry just makes it harder to play well.
Good luck! You'll need it.