It's not perfect, with some mods the sound can cut off, i tried my best to prevent it...
I share this because i have not seen such a mod for GZdoom and i hope maybe someone more skilled can perfect it or use it as base. Beware its just acs and decorate.
edit: changed code so "all monster killed" works after new monster spawns are killed
Download: http://www.mediafire.com/file/cn4f0vqv8bd8ii3/combos2.pk3
A short video:
Spoiler:Because someone asked, here is my own Blood mod as seen in the video.
edit: tweaked it more to my liking. its a mix of turok 2 (remaster) and Blood blood (when a monster dies)
Download: http://www.mediafire.com/file/ixt25dhupk054qu/Blut-only.pk3