Do yourself a favour and change the description. This is a very good game, especially if it really is your first one; far from horrible. If you say that, you'll either be perceived as fishing for compliments, or you'll just needlessly undervalue your game.
This is great. I don't think I've ever seen a space-shooter with close combat, nor did I see a spaceship-robot transformation. It's also nice that the art style is polished and consistent throughout the game.
The controls might be a bit wonky; moving with the mouse is unusual, to say the least (and moving with arrow keys moves the entire webpage since the default events weren't blocked).
With the mouse, you also continue to move and shoot if you move the cursor out of the screen.
The boss is pretty interesting, but after shooting from the laser, he perhaps starts shooting from the top and bottom canyon too soon. The rest of the level is okay, you could perhaps spice it up a little by adding obstacles, or something which cannot be shot – because now I can just carpet-bomb the whole screen to keep enemies out of my way until I reach the boss.
Very well done; good luck with your future games.