Re: Penny's Pursuit
Probably a boring strat, but I kept using Bass Blast perk + Blover or Reinforcemint + Blover in almost every level without locked plants/belt.
I also used Imp Pear's PFE and took advantage of the power tiles (also brought Power Lily just in case) to significantly reduce the zombies' health so that my Pokra can easily defeat them.
Imp Pear is also useful in the don't spend suns level, and can kill a zombie by putting two IPs in front of them, especially in the beginning while preparing your defense.
In the case of locked plants or conveyor belts, duh, I just played Endless first to collect power ups, lol. Thankfully my plants levels are high enough to be able to beat locked plants/belt level without having to use power ups. That, except level 17 aka the legendary Magnifying Grass level, where I just spammed power toss.