Space Invaders Infinity Gene

Play through all the levels on easy difficulty using your weapon of choice (Weapons are unlocked as you progress through the game,more points=faster unlocks). I found the field weapon to be most effective, especially when powered up with some tricolor orbs but i found some of the bosses, like the crab for example, were easier taken out using the wave or lock on weapons. Once you have unlocked all the levels you can start up the other difficulties and play the final level, 5-6, to unlock those achievements too. On the final level, the field weapon makes mincemeat of the boss there no matter the diffculty. Skipping the credits does not affect achievements.

Change the difficulty and stock in the options menu from the main menu and then go into game modes to play with your selected options.

Eventually you'll unlock the ability to have 5-7-9 stock ships to utilise which makes dying a bit less painless, but on easy mode this really shouldnt be an issue for you. This is also helpful for challenge and bonus levels.

To unlock Hard you need to beat the game on Easy or Normal. To unlock Insane, you need to beat all of the bonus levels up to 2-6, which arent too painful. To unlock Nightmare, you first need to complete all of the challenge levels.

Level 5-6 is the penultimate wave, & relatively easy using the field weapon. Simply take out all of the UFO's @ the start & collect all the power-ups to get your weapon to maximum circumference. Then stay in the middle of the screen to get past all the gates & finally get the boss inside the limit of your weapon.

Once he's dead the game will revert back to wave 0, but instead of a full line-up of old-school invaders you'll be faced with just one. Take a few pot-shots to get your timing right, then nail him. Job done.