Two people, one phone, no accounts to set up — shared-screen games are the simplest kind of multiplayer there is. They work by splitting the screen or the controls so each player gets a side. Here is how the format works, which genres suit it, and what makes a good pick for two.
There are two common layouts. Split-screen turns the phone sideways and gives each player half the display with mirrored controls, which suits duels and races. Shared-screen puts both players on one board and alternates turns, which suits card games and puzzles. Neither needs a connection between devices, so there is nothing to pair, log into or wait for.
Reaction duels are the classic: two buttons, one screen, whoever taps better wins. Air-hockey and pong-style games suit the split layout perfectly. Turn-based board and card games work because only one player touches the screen at a time. Avoid anything needing precise multi-finger control, since four thumbs on one small display quickly get in each other way.
Nobody wants to install an app to play one round with a friend. A browser game opens from a link on whichever phone is nearest and works on any device, so a mismatched pair of phones is not a problem. SmallWebGame has original casual and action titles that run instantly in a mobile browser, free and with no sign-up needed for either player.
Can two people play on one phone without internet?
Shared-screen games need no device-to-device connection. A browser version still needs a connection to load the page, but usually not to keep playing.
Is a bigger screen better for two players?
Yes. A tablet or a phone held sideways gives each player more room, which matters most in split-screen reaction games where thumbs compete for space.