Well... first, congratulations for your first game! especially for the Unity section!
Second, let's see... recommendations:
1) Improve gameplay: the movements of the spaceship are hard to control.
2) Improve variety: people love variety, add a few more game modes or space ships or asteroids!.
3) Improve performance: sometimes it's just make your browser blow.
Keep up the good work!
To beat Survival:
You will need: Piercing block, Eye Block, Booster Block.
How to: Start stacking the piercing blocks and in the top put a Booster Block, in the second row do the same but in the middle add a. Eye Block. Repeat.
Here's an image that shows my strategy: http://i54.tinypic.com/sqjxbl.png
Vote +1 if this was useful to you!