Radiant Silvergun

First and foremost, you CAN change settings to make this achievement even easier. Choose Single Player > Arcade Mode > Normal Play. Now you will have a few options that you can alter. Change the difficulty to Very Easy, start with 10 ships, and extension every 1,000,000. You can even run out of lives and use continues.

You only need to find one hidden bonus to get this easy achievement. The first and easiest one you can get is at the very beginning of the game. Start up Arcade mode. As soon as you can move, go to the very bottom right of the screen and press and hold the X button attack. A small dog icon will pop up, bark, and it will say Secret. The achievement will then unlock.