It's been absolutely ages since I played Asteroids so I can't comment in terms of original features or faithfulness to the original.
To be honest it's not 100% accurate.
-I agree that the ship needs more inertia to feel like I'm in space, man.
Yeah, I'm working on that. I think I already made it better, but I have to polish it a bit more
-Cool parallax effect you've got with the stars
Haha, thanks! I read so many tutorials on how to do this and then I tried it myself and was quite pleased with the result.
-I like very much that the aliens are all different visually, and they all look cool. Though this somehow makes it disapointing that they behave identically. What about different enemies moving and attacking in different ways? Then you could give more or less points depending on how difficult that enemy is to defeat.
That's a good point! I'll consider it.
-In the above case you could display the points value of each enemy upon their death, so that I know which ones are worth the risk of gunning for.
Already implemented in current version. A friend of mine had the same idea and it makes the game more arcade-ish.
-It felt totally unfair that enemy bullets can wrap around space and kick your ass, up your ass.
Yeah, I should remove this. I don't feel very happy with it either.
-The window is very small and that makes the action, not to mention your cool pixel work, a little hard to see. I could understand if it was made for the mobile web, but for desktop users you might think about scaling up or providing options to resize the window.
The art is not done by me. It's from Oryx, who probably is best known for his Lo-Fi dungeon graphic set. He's a regular on this forum, also. Check out his site:
http://oryxdesignlab.com/.
About the window size: It originally was 480x320, but it's also fixed in the current version. Now it's 640x400 and it's much easier to play this way.
I updated the first post with the link to a more recent gameplay video.
Thanks again for the nice tips and sorry for the late answer.