In normal mode, the player has to beat the zombies at level 1.
Difficulty
Being the first level of Dark Ages, the player gets to experience not having sun fall from the sky every now and then. As a result, cheap sun-producing plants and cheap attacking plants should be used. The zombies are not very threatening by themselves, the tombstones can be quite a nuisance however.
Waves
The small number next to the zombie icon means that zombie will always appear in that lane, with 1 being the topmost lane and 5 being the bottommost lane.
If necessary, Plant Food should be used to quickly get rid of the zombies.
In hard mode, the player has to defeat leveled-up zombies.
Difficulty
With leveled-up zombies, strong attacking plants or leveled up plants is a must. Other than that, it can be beated in a similar fashion to normal mode.
Strategies
Do as what you did in normal mode, but with leveled up zombies.
Walkthroughs
Plants vs. Zombies 2 (China) - Vigorous Broccoli MAX 4 level - Dark Ages Night 1 (Ep.143)