[2020] what happened to simple zombies?

Of note, Spider zombies can spawn at any time during the night, but, tbh they're not much of a threat...90% of the time they miss their leap attack, and they barely attack aside from that.

However, Night Time now has a chance to spawn Feral Zombies, even on day 1- It's a low chance, and they die instantly upon the chime of the morning bell (4:30am by default); These night spawn have a small chance of appearing and are just to make the nights more tense and dangerous- You can totally avoid em by just not being out where new zombies can spawn at night. Ferals cannot spawn during the day until way later in the game as others have indicated.

You honestly shouldn't still be running around at night on day 1; You should have found a place to stay and settled down and crafting items and figuring out your plan of attack; Or perhaps down in a mine quietly mining...But definitely not out wandering.

On the subject of difficulty balance for new players, it's worth noting that the devs stepped down the default difficulty setting a notch, in recognition that overall things have gotten harder than they used to be.