Needs more work
Look, the game concept is not bad per se. Nor original, but entertaining notheless. My observations include that it doesn't have much visual flare and also doesn't have any sound, which would have compensated for this flaw.
Also, notice how sometimes the alien spawns right at your location? That's a bothering glitch that could be worked around. With a little more effort and extra features you really could have something here.