The game is immensely fun, even though it is the bare minimum of a "Play and Upgrade" game. It induces challenge, and the confined space and time to draw a bow are factors that not only make the game harder, but increase enjoyment. I found the game very basic however, and I mean, very, very basic. Bosses are what you expect from generic bosses and upgrades likewise. However, the increase in difficulty throughout each wave, without introducing more than four soldiers was astonishing. By increasing the archers' ability was a stroke a gaming genius. Due to the simplicity of the game, I can't give it more than a three, but it made my day, so a three and a half should suffice.
Now to tips! What would a review be without tips?
1) Play it smart, don't charge your arrows all the way and take a hit for it! Shoot rapidly, and conserve your hitpoints.
2) Pick upgrades you will USE! I like speed, as constant movement is a must here.
3) Constant movement, move as much as you can when those arrows are whizzing by, and slow down to shoot when you are not overwhelmed with enemy firepower.
4) When fighting a boss, watch his bow, if he charges his bow, (This can be detected when the bow string is pulled back to full draw) don't seize this opportunity to shoot, but to evade. His arrows move remarkably fast when charged to the full extent, and will most likely devastate if you try to catch them with your chest.
An armor upgrade would be nice
Perhaps a goal or quest to strive for
All in all, as I'm sure most of you do not want to read an essay, I found the game enjoyable, but for gamers who crave longevity in their games, this isn't for you