Rescue Rover

Rescue Rover is a computer puzzle game from id Software, published by Softdisk in 1991. The game was distributed as shareware, with the first 10 levels making up the shareware version, and another 20 levels being present in the registered version. This is one of several games written by id to fulfill their contractual obligation to produce games for Softdisk, where the id founders formerly were employed. A sequel, Rescue Rover 2, soon followed. Source: Wikipedia, "Rescue Rover", available under the CC-BY-SA License.