A fellow classic recreator! And a good job at that!
Arrow keys appear to be inverted, but WASD seem to work fine. I'd also like to see an autofire. After a while my hand got a little tired. But that could just be personal preference.
Overall, a nice recreation of the classic. Reading the comments below, it looks like you had several more things you wanted to add. Mind if I ask what they were and if you plan on continuing with them? (Also, totally get cutting stuff. Did the same thing.)