Great game. Definitely beatable. The difficulty does ramp up on some of the bosses, especially at the end.
The game takes about an hour to complete.
There are several little hidden weapons in the game you can locate.
The only major drawback is that the special weapons you find are a one time use. Once you run out of ammo, you don't get a refill on it. You can die and respawn with the special weapon, but again, once it's empty that all you get.