It is difficult to find a game similar to countrycide, the closest thing from my point of view is probably between:

-the ashes saga (Ashes 2063, Ashes Afterglow and Ashes Hard reset), where you live in a post apocalyptic world...

-Shrine 1 and 2 (Free to play on steam, so famous that they appear as independent games when they are a doom WAD), with demons, angels...

-Lycanthorn 2 (Also free in the steam store and it is a doom wad, when you open it it also gives you the option to play the first one), different but not losing the essence of the previous one...

-Vomitoreum (this is paid on steam), much more similar to shrine 1 and 2...

If you play them, you will realize that the Ashes saga are probably the most similar...the others' graphic concepts are quite different, but not in terms of enemies, etc.

Thanks bro I apprecaite that, I'll give them a look