Nightmare Reaper was good fun for me. Gameplay-wise it feels good with a plethora of weapons with randomized stats to keep things interesting (though I did feel locked into one really good weapon I found for most of the game, so I didn't get to try a lot of them). Fast shooting, some puzzle-ish elements, fluid movement, tons of unlocks with neat (if simple) minigames, and enough narrative to keep you wondering what's happening. The soundtrack is pretty awesome too if you like djenty metal a la the new DOOM stuff.

My only primary complaint is that the game is a bit too long. It didn't bother me much since I was still having fun with it, but others might find that themselves in a slog pretty easily.

Overall, if you like boomer shooters, roguelite elements, and a neat retro style, definitely give Nightmare Reaper a go.