Two Rex is a dual-control puzzle: you're moving two dinosaurs simultaneously with the same inputs, and both have to reach their goals.
That single constraint generates all the difficulty. A move that helps one character usually hurts the other, so levels are about finding the sequence that serves both.
Both characters move with the same input, so every move affects both. Using walls to block one while moving the other is the main technique.
Yes — a gentle co-ordination puzzle with no violence.
Yes — a light 2D game with nothing to install.