Bug Bot Imps will be introduced as an ambush obstacle, which absorb 13.5 normal damage shots, more than the average Imp. They will be a bit harder for the player to deal with if he or she is not careful. In addition, the Jetpack Zombie makes a reappearance, so the player should prepare to defend against those.
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 one.
Plant two columns of sun-producing plants (one if you choose the Twin Sunflower). Play as you usually do in the few first waves. Plant defensive plants quickly.
After a while, an ambush (Bot Swarm) will be called and four Bug Bot Imps will fall from the sky. Unlike the other Imps you met before, this one is tougher. Immediately plant a defensive plant if you did not plant it on the lane where Bug Bot Imps are on. Fortunately, they land on the eighth and ninth columns, so they should not be a threat.
When you enter "Final Wave" stage, another ambush will be summoned and more Bug Bot Imps will land. Use a Cherry Bomb to destroy a half of them, and the rest, you need to keep them busy on eating your plants. Use another Cherry Bomb and the level is finished.
Do not forget to do things like plant plants on Power Tiles, using Plant Food on them, and plant as many offensive plants as you can. You may use Winter Melons to slow down Bug Bot Imps so as not only to do damage to them, but to also slow them down.