Have some tips...
-Add sound effects and music
-Make the graphics a bit more interesting. A one color triangle and a grey background are REALLY dull. At least make some kind of basic ship design.
-Work on the movement, it's really jerky and that's annoying
-If you want to make a good game, you need to add something unique. Powerups, challenges, anything.
It's not bad for a first game. Just work on these things.