I played this one before outside DD and it's one of my favorites, I finished all chapters and feel like I could play it forever as long as you throw more levels at me.
I do have a few nitpicks and suggestions though.
- The turrets that aim at you should reset their attack timer if they lose track of you, right now they ready up a shot and might fire at any moment when you come back to them, I have to keep track of their timers in my head. It does add some nuance to them but it feels inconsistent
- The cutscenes and "storyline" don't mesh well with the game itself. Communism is not what comes to mind when I see sterile test rooms and such
- Some hitboxes feel larger than they should be, particularly the bullets. I think close calls are more satisfying than bullshit "that didn't even hit me" deaths