Way too simple maps.

For "generic" map: it looks like a learning map.
For "Pulsar" map: short but noticeable better than "generic".
For "Zwiffle" map: the map is umplayable without noclip cheat because the ceiling is too low and you can't move.

I certainly would not call generic's and Pulsar's maps “way too simple”; quite the contrary. They are both very impressive for speedmaps, in terms of both visuals and gameplay.

Zwiffle's map is more standard speedmap fare and not really my cup of tea.

And Zwiffle's map is not always unplayable. I loaded the map a few times and the player avatar was stuck about one third of the time; the rest of the time it was fine. I could be wrong, but I suspect the ceiling height is right at the lower limit, so sometimes the player gets stuck and sometimes not. Perhaps that was the point of the map: to make something that is as low as possible and still playable.

You only need to use noclip once at the beginning, you can turn it off after moving a bit and then the map works fine.

I see zwiffle was inspired by Wolfenstein 3D...