definitely couldn't make it to the boss ;) solid concept, didn't ever feel unfair - however, I do have a few constructive bits of criticism!
- menu navigation is a little off :P had to press up to go down on the first item
- a lot of the enemies at the start have waaaaayyy too much health
- the lives didn't seem to update properly - there was always 1 less shown visually than I had
- needed more juice to be honest. Getting hit didn't really feel like anything happened, killing enemies wasn't particularly satisfying, hell - even the fact that the gun autofired meant I wasn't really doing anything! It just needed more "oomph" :P
- I could legit just stay in the centre and move slightly left and right for a long time. It wasn't til the two enemies came in from the sides and did a big circle of bullets that I actually had to move from my mostly safe spot
Those are all really minor nitpicks though. A solid entry, visually it looks great, there are just a few little things holding it back from being a great entry! Also, high score table please? Even just local, but http://www.dreamlo.com is a great online leaderboard service that is really easy to use with Unity :)