ZDoom

I missed them, too.

I'd be just happy if it just gets printed out

Fixed. But please don't come back and complain that the messages are printed at the center of the screen.

I probably will post a list of missing HUD messages when you successfully buy an something from a merchant (and other missing HUD messages, when I go through the original game with GZDoom and Vavoom). I'm not sure if there's a bug preventing their output.. but I will compile a list and post it if necessary.

Here are a list of missing HUD messages:
When you kill certain bosses, there is no declaration of them saying that they have been killed. This list includes Macil (2nd form), the Bishop, the Loremaster, and the Oracle.
The message itself is stated as "You have killed (fill in boss name)."

When picking up the Prison Key from Warden Montag, the HUD message telling you that you've picked up the key has the word "Prison" spelled wrong.

Edit:
Additionally, a door that requires the Silver Key is supposed to say "You need a Silver Key" if you don't have it.
The switch that requires the Red/Blue Crystal is supposed to say "You need the Red/Blue Crystal"