When I reincarnate, Im a cube!? Steam

This game is an FPS where you fight against demons in
a voxel art world by equipping yourself with various weapons.

When you wipe out the demons in a stage,
you clear the quest and can challenge a new quest.

You can also acquire new equipment by picking up items
that are dropped when you defeat demons.

After dying of exhaustion on Earth, I seem to have been
reincarnated in another world, but...

The landscape that unfolded there was like an old video game,
a world where everything was a cube.

Then the fairy Erin appeared and led me on a journey
through this cubic world.