It's cool and all and I typically enjoy lowres renditions... unless, it actually impacts gameplay.

Since the gameplay is so much about 4D, clarity in what you see becomes more important and the extremely low resolution actually impairs the player rather than serve a positive (typically 'leaves more to the imagination').

It wouldn't take much of an effort to double or triple the resolution which I think would help the gameplay.

The reason it is so low res is actually more interesting than simple aesthetic choice. Think about the sensor(or eye) needed to view a 3d scene, it is 2d right. So this is a 3d sensor(voxels) for a simulated 4d camera. and then we are looking at the 3d sensor. (with our 2d sensor(eyes)), it's sensor inception.

So it is as low res as it is because it is a bunch of voxels simulating a 4d camera.

The dev put out an interesting video on the topic.

Agreed this is not even 4d Wolfenstein but still a really neat concept