how to go forever in endless:
first, get 2 infini-nuts, an imitator, a puffshroom, and a mushroom grotto. find an enemy that cant do more than 6 damage, set up both nuts, and then use the imitator to dry out everything except the grotto and puffshroom.
use the grotto over and over until you have a couple hundred reroll powerups. Any level can now be beaten by rerolling and spamming puffshroom.
once you have a lot of coins, find a potted chomper and a dr dave's supplier. Mow all your cards except the supplier. you can now beat any level just by spamming dr dave until the chomper kills everything.
(please dont remove this strategy, its a bit broken but it makes the game fun)