Highway to the Danger Room

Highway to the Danger Room is the Endless Zone in Modern Day. The starting plants are Moonflower, Nightshade, Shadow-shroom and Dusk Lobber. As usual, the player can expect one flag levels at the beginning but progressively getting harder as the player advances. Gimmicks from other worlds are not present here. The portals are also the only way that zombies from other worlds can appear. There is no way that the player can know whatever portals can appear in a level, and while the portals start with less dangerous zombies such as 8-Bit Zombies and Dodo Rider Zombie, later on more than 3 portals can appear at once and they can spawn much more dangerous zombies such as Octo Zombies and Weasel Hoarders.

Strategy 1
Required plants: Note: This strategy is only tested up to level 80, it may not work on higher levels. If the zombies are going to win, resort to power-ups, if available.
 * Plant two rows of Primal Sunflowers.
 * In front of it, plant a row of Cold Snapdragons.
 * Use Escape Root and Blover to get rid of annoying Zombies that will appear throughout the level.
 * Use Chard Guard when needed.
 * When you get enough sun, dig up a row of Primal Sunflowers and plant Winter Melons, do the same with the other row of Primal Sunflowers, but do it when you have enough sun.
 * Power Lily will help you get enough sun using Plant Food.
 * The Cold Snapdragon will help clear off Zombie Chickens, Ice Weasels, Shield Zombies, and such, while the Winter Melons will take care of Excavator Zombies, Turquoise Skull Zombies, Robo-Cone Zombies, and others.
 * You have Blover, so use it.
 * All-Stars are the only Zombie that can ruin this strategy, as they move fast and can destroy a plant instantly, try to use Plant Food on Cold Snapdragons.
 * Do not plant anything from the fifth column onward, since zombies can eat them real quickly.
 * If there are a lot of zombies in a lane, use Chard Guard and Blover together to destroy them.
 * And finally, if you do not have much sun, use Plant Food on a Primal Sunflower which you will place somewhere on the lawn.

Trivia

 * Highway to the Danger Room is a reference to the song Danger Zone by Kenny Loggins, which had previously been used in the trailer for Plants vs. Zombies: Garden Warfare 2.
 * Furthermore, it also alludes the internal name for Endless Zones on their corresponding game codes, namely "Danger Room".
 * The Neon Mixtape Tour portal can spawn 8-Bit Zombies, even though there is no arcade machine.
 * The Travel Log refers this endless zone as "Highway to the Danger Zone". This is the second error on the Travel Log involving Endless Zones.
 * The other one is about Greatest Hits, which says "Unlock 80s' Danger Room!" instead of "Unlock Greatest Hits!"
 * Sometimes, if the player starts Highway to the Danger Room for the first time, the player may receive wrong starting plants. Instead of Modern Day plants, one may receive plants from Player's House (Sunflower, Peashooter, and Wall-nut).
 * Highway to the Danger Room currently holds the record for the longest Endless Zone name, having five words, while others typically have two to three words.
 * It is the only Endless Zone to have two possible candidates to appear as the first zombie besides Basic Zombie. In this case, the zombies that may appear are Imp and Super-Fan Imp. If this happens, then the next wave will be triggered immediately.
 * This is the only level that portals can be spawn on the portal that has spawned already, for example the Wild West portal can be spawned on a Far Future portal that has been spawned here for a while.