A free program for Android, by Gerhard Stein.
Commander Genius is a mod for the free game, Commander Keen. It contains several game modes, including Campaign, Survival, and multiplayer. All the games are based on the same world and gameplay mechanics, but they differ in terms of difficulty, strategy, and game mechanics.
In the Campaign mode, the player controls a single character and must complete a series of missions. These missions vary in terms of task, such as killing X number of enemy units, locating Y number of treasure chests, etc. The player can choose to complete the missions in one of three difficulty levels, which vary in terms of the enemy units and treasure chests that need to be killed.
The Survival mode is based on the multiplayer mode, which allows players to play with other people online. In this mode, the player is not the only one who is in the game. There are other players, and the goal is to kill the enemy player. However, the other players are not controlled by the computer, so you can kill them and move freely.