Chip's Challenge
I've finally managed to start turning on Twentieth Century. I was able to back it up, so if anything happens, it should be a little easier to restore.
Chips Challenge is a game that I never had growing up, and I think I only played it once or twice somewhere. This is a puzzle game from 1989, with 16 color graphics! It is abandonware.
The gameplay is pretty simple: navigate through a level to collect computer chips to unlock the door to the next level. There are many level elements, like water, ice, fire, conveyors, and fire. Some levels have boots that you can use to walk over these barriers. Some elements are active, like portals, creatures, replicators, and walls that appear once you try to walk on them. Sometimes there are doors that you need to find keys to.
The thing I don't like about this game is the timer. One level has you going around collecting chips at the far end of four mazes, in which I discovered that boots have weight, slow you down, and the level is deliberately designed around it. Also, I tend to not be that good at these kinds of games. Either that, or the levels tend to be claustrophobic. Levels are all too eager to send you through labyrinths. There's not much space to think, unlike Portal 2.
Edit May 2015: Wow, something happened. The original owner regained the rights to this, and it's (up until now) unreleased sequel, and both are on Steam.
You can't complain about this anymore. It's perfect!