Check out the rest of the tutorial that the background comes from. There are sections for mini-bosses, power-ups, and it talks a bit about continuity of theme. All of those things would be improvements on what you have posted. Keep trying!
Author Comments
This is the sequel to Deep Space! In this one I have added a huge amount of extra features! And it is now a side-scroller!
When I first saw this up for review, I was unimpressed. However, this game is, somewhat surprisingly, actually fairly well done. Sure, there aren't many features, and the graphics are extremely simplistic, but what has been added is fairly well implemented. A 3.5/5 from me.
It's a pretty generic shooter. I don't notice any "extra" features in this one, unless you mean the background which is nice to look at. I played a couple of times but the enemies, your ship, the difficulty, etc. do not change. The music was on a loop but that ended about 3-4 minutes in so I was left with silence. I suggest you first improve the re-playability, of it, a level system or similar would be an easy change that amps up difficulty after a certain point value is reached. Onscreen pickups would be useful as well to upgrade/heal your ship. Finally, the framerate was still a bit choppy for a fairly simple game.
Overall: make it smoother, make it have replay value, fix the music issue, and make your ship more entertaining to use and try again.
Below average; the game does not have horizontal perimeters. IE: i can press up and just keep sending my spaceship into the sky, avoiding all incoming damage, indefinitely. I like the background and I think you should stick with a more detailed black and white game instead of having a decent background and the plainest, most boring sprites for the spaceship and enemy ships. Collision boxes are good, narrowly avoiding rockets was neat. Really poor display and 0 background information. A side scroller it is, but its just boring.
Recommendation: make the whole game black and white, refurbish HUD, (points and health bar), actually include bonus features, mmm donuts.
Alright.. but some suggestions, i'm a flash coder myself, so i know how it feels :)
Where did you get that background? it looks real nice :) I think its a tutorial on Kongregate.. right?
anyway, graphics where really nice, but a bit chunky, (not smooth)
you should add little bumpers, so you can't go off the screen, and maybe
make a variable that goes up every 10 or so frames, then make it spawn more alien ships :)