"We understand that many of you will not like having only 8 directions to shoot at (...) It would also be virtually impossible to have 360 directions, since this would require creating and animating graphics for each degree."
This has to be the greatest B-word i've ever heard and I consider it insulting to use it as an "apology".
You didn't need graphics. You could just leave the 8-dir sprites as is, and make JUST BULLETS travel on a 360º radius. Very few people would actually care. I wouldn't.
The issue isn't precisely the 8-dir shooting area, but properly that coupled with the game design. Cyberdogs has a 8-dir shoot style and is a great game, because enemies don't behave the way they behave in this game, nor levels follow the same design.
Also, there are plenty "Mecha" games that are older and have fully functional 360º radius of fire.
Now, about the hitboxes, they are unforgiving, and quite unfair.
Game becomes boring quickly.
Difficulty is useless - Win one stage on demigod for the medal and the rest on wimp. Still awards all medals.
Summing up, a good premise but a bad execution that ruined what could have been a great game.