Fate of Io's gameplay is unique. Although certain aspects of it are similar to aspects of other games, the overall experience is intended to be nothing like any game we know of.
The gameplay of Fate of Io consists primarily of creative problem solving. The player controls a party of one to four characters. Each character has a unique set of abilities which can be used to manipulate the environment in many ways. It is up to the player to invent ways to use the characters' abilities to get past each obstacle the characters encounter.
These "obstacles" come in many forms. Some are enemies which must be fought. Others are more passive puzzles which must be solved. In both cases, there will usually be many possible solutions to the problem. In fact, it will often be possible for the player to invent solutions that the developers didn't think of. However, in most cases, the player will need to think carefully about their actions. Brute force will generally not be a successful solution to either battles or puzzles.
There is nothing preventing the characters from splitting up during gameplay. In fact, they may have to split up to get through some areas. The characters don't automatically follow any one lead character. Instead, if the player wants to move all of the characters at once, they must select all of them and tell them all to move.
For more details about Fate of Io's gameplay, use the navigation bar at the left to read this section's sub-sections.
To download a preliminary outline of the game's challenges, the MS Excel sheet can be found here.