Isn't it convenient that your neighbor is so helpful in your fight against us zombies? Crazy David's apparent incompetence is only eclipsed by his usefulness. However, with one secret word my sleeper agent will turn against you. Listen to me David, "Hypno-Zombnosis".
Zombot Tomorrow-tron is a well-rounded mechanized walker that is capable of neutralizing plants and as well as Power Tiles with its missile attack and absorbing tons of damage. Not only that, but it is also capable of calling durable zombies such as Shield Zombie, Future Buckethead Zombie, Gargantuar Prime, and Mecha-Football Zombie. The threat level is less for the first phase and focuses more on summoning zombies. With only Laser Beans and Citrons for self-defense, it will take some time to kill zombies despite the Infi-nuts given as well.
At the second phase, it will start calling more battle hardened mechanized walkers such as Gargantuar Primes and will start as well utilizing its infamous Charge & Assault, increasing the handicap of the level. Also at this moment, Plant Foods are slowly becoming rare.
At the final phase, the Zombot Tomorrow-tron will start calling on Mecha-Football Zombies and Shield Zombies to increase the difficulty further, plus Plant Foods at this state are given from minimal probability to zero probability.
Don't plant on power tiles so you don't lose all you plants to one attack
In the first phase, consider using Plant Food to stop missile attacks (by using Plant Food on the targeted plant).
E.M.Peach and Magnifying Grass (which needs sun) are not given. Therefore plan at your best. Stall the zombies instead with Laser Bean's or Citron's Plant Food ability. Keep in mind that Laser Bean works well as it can greatly damage machines while Citron can destroy one.
Infi-nuts should be used on the first phase. It becomes useless on the second and third phases.
Save your Blovers for the first and third phase. No need to waste one for thrown Bug Bot Imps. Otherwise you will risk chances during third phase. It is really useful during the first phase to destroy all Jetpack Zombies instantly, as they can carry Plant Food that you may need early on, and they can also get in the way of your Citrons firing at stronger zombies.
Like any other Zombots it is divided into three healths and statuses. Depending on its status, it will summon more zombies and use its charge attack.
Phase one - Future Zombies and its Conehead and Buckethead variants, Jetpack Zombies, and Shield Zombies are only summoned. Farm for Plant Food first for the next phase or you will risk a lawn mower.
Phase two - Gargantuar Primes and Bug Bot Imps are now summoned. Also, Jetpack Zombies and Shield Zombies are discarded from the field. Gargantuar Prime's Lasers can be of threat at this moment and you might lose two rows of plants by chance. Feed the Citron with Plant Food to deal with Gargantuar Primes while Laser Beans for compressed zombies. Zombies tend to be compressed together when summoned in this phase.
Phase three - Mecha-Football Zombies are finally summoned and Gargantuar Primes and Bug Bot Imps are discarded from the field, Shield Zombies and Jetpack Zombies will come back. Stall for time by planting things directly in front of the Mecha-Football Zombies and use Plant Food on the Power Tile sets as much as you can. Usually the Zombot Tomorrow-tron will not be able to hold up against so many Plant Food attacks and will easily be defeated at this point.
As always, stall the zombies which are the highest threats.
If you are determined to stop the zombies from advancing on the third stage but also want to avoid letting the Mecha-Football Zombie bulldoze your plants and interfere with your chance to give your plants Plant Food, follow this step: Place the Infi-nut in a lane away from the path of the Tomorrow-tron, because you never know when the Mecha-Football Zombie will spawn onto the map and how many will spawn. With the shield ability, it will not bulldoze the plants and interfere with your concentration of giving your plants Plant Food. As soon as you see one fully spawned, immediately give the Infi-nut Plant Food to block all the lanes. Then, quickly give the Laser Bean Plant Food to take away half its health as well as clear any other zombies that are in its way and let your Citrons finish the job. If the Zombot Tomorrow-tron changes lanes and an Infi-nut is in its path, dig it out, re-plant a new one in a different lane, and give it Plant Food.
Sometimes, the charge attack can actually be useful. If Zomboss is about to charge in lanes with problematic zombies, let him do it. While he will destroy your plants, he will also prevent you from needing to use lawn mowers. This can also earn you Plant Food, especially in phase three, as in phase three, Plant Food is scarce and at the same time, it requires you to consume one Plant Food before acquiring another one.
To avoid wasting Plant Food, it will make the boss harder. Make sure they are lined up correctly so you can maximize damage and accuracy to both Dr. Zomboss and the zombies.
Upon completing the level, Crazy Dave appears and calls the level "hypno-MAZING". This may have been hinting at Hypno-shroom, which would make a return as a premium plant along with the next world, Dark Ages.