S.E.M.I. – Side Effects May Include is a cooperative online game about escaping a special clinic, with players taking the role of patients caught in a hazardous, unpredictable environment. Up to four players can work together, but the setup also makes friends potential troublemakers: voice chat is part of coordinating through rooms, and the game explicitly encourages sabotage as well as assistance. That blend gives the cooperative format a mischievous edge rather than making teamwork the only possible approach.
Its rooms combine brawls, puzzles, deadly traps and platforming, with a single mistake capable of knocking out the squad. Random generation reshuffles locations from rooms featuring changing gravity, moving walls and other hazards. Pills add another layer of uncertainty by granting unusual abilities: one can make a character an invulnerable monster before leaving them helpless, while another makes them tiny or gigantic. The stated design leans into clumsy controls, shifting powers and the need to adapt together, rather than presenting escape as a straightforward fight through fixed stages.
The game lists both single-player and online co-op, so its player-count context includes more than one way to approach the clinic, even though the premise foregrounds a group escape. Successful escapes bring a medical report, and players can unlock costumes and decorations, giving the repeated runs a playful framing beyond survival. S.E.M.I. is therefore best understood as a co-op escape game built around volatile abilities, generated room layouts and social coordination that can turn into disruption.
