Ember Boy and Ripple Girl

Ember Boy and Ripple Girl asks you to guide two elemental characters through the same obstacle-filled level at once, and the twist is that a hazard harmless to one of them can be instantly fatal to the other. Fire obstacles that Ember Boy can walk straight through will stop Ripple Girl in her tracks, while water hazards work the exact opposite way, so clearing a level means constantly routing each character around whatever specifically threatens them rather than finding one safe path for both. Because their routes through a level rarely match, planning has to account for two separate paths converging at the exit rather than a single shared solution. Later levels layer in more of both hazard types close together, which forces genuinely split attention between two characters instead of treating one as an afterthought while focusing on the other.