It's a tough one we haven't seen before. Wall nuts, spikeweeds, puff shroom and fume shroom. Zombies can't trample the flowers. And you'll see 3 gargantuar zombies.
You only get 5 wallnuts so if one is almost eaten you have to dig it up and wait for another to come to replace it.
I was able to do it on my 3rd or 4th try by using a lot of powerups. But I have a few more profiles left to try it on and am wondering if anyone had a successful strategy. Mine was wallnuts 2 columns to the right of the flowers, with spikeweeds in front of them. Then puff/fume shrooms behind the wallnuts. Plant food mostly on fume shrooms to move everything back.
This is one where the mower launcher comes in handy, launch that mower at a Garg to save yourself some plant food. This only works once a level though. --- I should go.
It was on again today. This is my first time playing it. It is difficult, but its difficulty mostly lies in strict timing and allocation of plants.
Board Arrangement: I put the 5 Walnuts directly in front of the flowers; the 10 Fume-Shrooms behind the Walnuts; and the 10 Spikeweeds in front of the Walnuts. I found that the Puff-Shrooms are basically useless; I only use them for distracting zombies or for extra DPS against high-HP zombies (buckethead, knight) at the backmost column. Keep the distribution of the plants among the rows as uniformly as you can, especially in the early phases.
Plant Food: Plant food is pretty scarce here, so conserve. Use them only on Fume-Shrooms, and only against Gargantuars, when these are already just before the flower line. Doing so will be push the Gargantuars back to the first row, thus maximizing damage. It takes 2 plant food to kill a Gargantuar, and with there being 3 of them, you'd need at the very least 6 to win. It's hard if not impossible to stop or delay them while they're marching.
Gargantuar Appearances: There are 3 Gargantuars in the whole level. In their first appearance, the Gargantuar appears alone in the middle rowódistract it using Puff-Shrooms or other unwanted plants and kill it using 1-2 plant food. The second appearance involves 2 Gargantuars on the 2nd and the 4th rows (the two rows beside the middle). Distraction won't be too effective here, but pay attention to the other rows not under attack by the Gargantuars because they may be overrun. You may want to dig out the Walnuts on the 2nd and the 4th rows (because they'll be destroyed by the Gargantuars anyway) so that you can have some slack for the other rows. Afterwards, you may want to add Puff-Shrooms on the 2nd and the 4th rows for additional DPS.
Walnut Maintenance: Frequent Walnut replacement is key to winning here. The replacement of Walnuts should be started when most other plants have already been planted (so that the conveyor will not be too clogged). Walnut replacement should be done whenever there aren't enemies in a row and most especially on rows that have just been attacked by high-HP zombies.