we need a actual wave based mode that lets us ride the train and counts day total, every day from 1 to however, and possibly infinite on the top right of the screen or something.

for every day the waves get more hp and damage, melee can still be used but gets more scarier as enemy damage eventually outscales player health, and you're more reliant on being careful with ammo

frost mode already exists but it isnt really a real wave mode cause it only incentivises fighting zombies occasionally and still has a guaranteed end, we need a mode with a infinite track.