Compilation comprised of clones of Space Invaders Part 2, Asteroids, Tetris and Kaboom!, along with a hidden bonus game.
To obtain the More Invaders! bonuses, clear out all of the invaders except for the one column at the farthest left of the screen. Saving the second one from the bottom for last will give you a 500 point bonus, while killing the one at the very bottom last will give you 1000.
On the game select screen, hold down button #2 and press 4 repeatedly until you arrive at the hidden game (after Spike's Water Balloons).