Pac-Mid (3DO, Mac, and Windows): The coolest of the easter eggs is happily also included in all 3 versions. To access this one, play level 61 ("X Marks the Spot"). This level features a single rainbow pyramid in the center of the landscape. Shoot it. If it doesn't come up purple, kill yourself and try again. Eventually, you'll get a new pit in the center of the X. Now, fall into that pit. Then go to the level grid and choose a level with limeys. From then on, until the next reboot, the limeys will have a wacky new look.
The Original Prototype (3DO version only) - All of the fundamental elements of Icebreaker were created in a little over a week as a programming exercise. The result, while terribly rough, still proved to be enormous fun, and was quickly turned into a commercial product. That original prototype is secretly included in the 3DO version. Here's how to access it. When you first load the CD, a large 3DO logo is displayed. It is replaced by a black screen, after which another, slightly smaller 3DO logo is displayed. As soon as you see this logo (but not before) press and hold the left shift and A buttons.
Multiple Lives (3DO version only) - A common complaint among playtesters of Icebreaker was the fact that you must clear the entire level without dying. "We want 3 lives!" they'd whine, "just like other video games!" So, we tried it. And as I predicted, it was lame. The challenge dropped way off and with it, the addictive gameplay. It's just too easy if you get multiple lives. However, if you have the 3DO version, you can judge this for yourself. Follow the same procedures as for the 3DO version, except press left shift and right shift together when the smaller 3DO logo appears. The words "Extra Lives Enabled" will appear at the bottom of the screen. You will then have 3 lives whenever you play, until the next reboot. But be aware - cheating in this manner will avail you not. The level grid will not be updated if you clear a level with multiple lives activated.
3DO Lander (3DO version only) - When I first started working at Magnet, there were only 3 other game programmers working there. Two of them were John Blakely and Glenn Ortner, a couple of fellow NASA fugitives who had done a version of the classic Lunar Lander arcade game as their 3DO programming exercise. When we were putting the finishing touches on Icebreaker, we decided to toss this little game into the mix as well. You can access it in the same manner as the original prototype, pressing B instead of A along with the left shift button when the smaller 3DO logo appears.
The Easter Lurker (Windows version only): The last easter egg appears only on the PC version and is similar to the Pac-Mid. This time, the way lurker pyramids look will be altered when the easter egg is activated. To make it happen, go to the level grid, and select level 124 ("The Cheese Shop"). Now, type the word "eggs". After this, proceed to to actual level, which will then be named "The Egg Shop," wherein the lurkers will look like they never have before.
Icebreaker: The Text Adventure (Mac/Windows versions): Andrew Plotkin, noted interactive fiction author, wrote a very amusing text version of the Icebreaker, which was included on the CD with the Mac and PC versions of the game.