Yeah... I actually got similar feedback on the shield during play testing, but it got put on the back log and didn't make it in time. I'm going to write the code for this today though since it seems to be the #1 issue!
As far as difficultly, the last commit I pushed before submitting was an attempt to add more variety and I did not test it well enough apparently because the day after I realized it was incredibly hard past wave 5. You can actually play the rebalanced version here: https://turtiesocks.github.io/pumpkin-palooza/
Note to other game jam reviewers, please play the version on itch before playing the above so you can evaluate the submission fairly!
Thanks for playing!