Wanted to say something similar the game is a lot harder than before ( not necessarily bad). I got to wave350 ( made a few mistakes) but had >1000% drop rate and black widow on the field and was still missing some items. The 2nd wedding ring was most annoying to wait for.
More info on drop rate increases can be found here: https://mazebert.com/2015/07/26/new-loot-function/ TLDR: Can't more than double base drops. Drop rate past certain point (~500%) has very small effect.
This not directly about the increase but drop rate in general. Plus this might be outdated with the rework. But still might be good to know thx.