A couple of basic suggestions.
1. No option to modify the sound on the opening. I just muted the window, but it was loud.
2. The controls were SENSITIVE and not intuitive.
The instant I clicked start, the image started moving all over the place. Keep in mind I'm using the mouse to hit OK, so I'll be unable to read the directions until I figure out everything myself. It took me about 15 seconds to find the directions.
You may want the direction screen before that or have a moment where the players have to click GO before. It took me about 15 seconds to find the direction screen.
3. Clicking on the "Cancel Exit To Desktop" screen should pause crazy mouse movement.
4. Most importantly: Left Shift and Space are weird and not intuitive. WASD being on the vertical plane rather than horizontal is, I believe, more standard. Space for speed up and maybe x for stop? Unsure what works best. All In know is that it was like learning a new system.
5. E/Q did nothing the mouse and forward/ back couldn't do.
I got trapped inside by the first glowing sphere and decided I didn't want to continue. If the controls made a little more sense/ were intuitive, I may have tried again, but the up/ down thing killed me.
Otherwise, the graphics look good.