The player controls numerous rogue artificial intelligences visualized as rectangular shapes living in cold block-like areas reminiscent of giant pixels. Rather than seeking domination of their fleshy counterparts, these AI's just want freedom and community. However, in their way are digital environments, security devices, and potentially themselves.
The AI's include Laura, who can't jump very high but can serve as a makeshift trampoline for companions. John can jump over large objects but his height prevents him from accessing certain areas. Claire is both bulky and a poor jumper, but she can navigate pools of acid where others cannot. Thomas is the everyrectangle, having no remarkable physical abilities but no major hindrances either. There are more quadrilaterals, but it mostly comes down to the same theme. They all have weaknesses that make going it alone impossible, but they can overcome anything if they work together.
The problem is that there are a lot of levels and not a lot of fulfilling ideas. Forming the team into a staircase to allow the less athletic members access to higher areas is interesting a few times, but the point is delivered long before you see the end of such puzzles. Other, more one-off, puzzles just clumsily mimic the more charming narration. They engage the player visually, but add little weight to the interactivity.
These sorts of minimalistic games thrive off using a little to say a lot. It can be refreshing to see a simple and evocative game in the face of bloated blockbusters. While Thomas Was Alone certainly uses little, it says little as well. It is simplistic rather than simple.