First off if you'd rather hunt down the pumpkins yourself but don't want to look in every level(not every 2020 level has a pumpkin hidden in it, only 10 of them) here's a list of the levels the pumpkins are hidden in(1 in each level). The initial entry, a message, no excuse, what's to come, redeployment, remix track 1, underneath, in the dark, my regrets, what remains.

And here's a short walkthrough leading up to each pumpkin to show where they're at.