Fun and simple, love it when I only need one hand to play. I think the two biggest things that stick out for me is 1) no music and 2) input delay, though it almost feels intentional. I think it could really help if you made the movement quicker and snappier, almost like a .3 second window where it whips into the cube and the user can rapidly tap them and feel each movement attached to each key press whereas right now, it feels like multiple commands get queued up and im waiting for them to execute.
As an added bonus, the way enemies have similar movement patterns, maybe when you add music you can add a rhythmic element? I am getting crypt of the necrodancer vibes just waiting to be unleashed. Nice work!