Short answer

Which free playable demos should I try?

MeetNewAI lists 9 free picks in playable demos. Start with Last Train to the Sea, Salmon Survival, Outerstead, Outermate, VybeNomad. Prices were checked on each official site; free plans can still have paid upgrades.

Every pick below was checked on its official site. Pricing changes, so confirm the current plan before you rely on it.

Salmon Survival

Live a salmon's life in a Nordic river, from hatching to the sea and back.

Free3DSimulation

Outerstead

A colony sim: four survivors, a forgotten world, one settlement to build.

Free2DSimulation

Outermate

A prison-escape sim where the daily routine keeps running around you.

Free2DSimulation

VybeNomad

A digital-nomad life sim: pick a city, take contracts, cover rent and food.

Free2DSimulation

Stardust Isles

Explore endless 3D islands and collect stardust; everything is generated by code.

Free3DExploration

FlagGuessr

Name the country for each flag, then find it on the map.

Free2DGeography

CritterTown

Build a character, then walk into Willowbrook.

Free2DSimulation

Rocket Yard

A rocket builder that runs in the browser from its itch.io page.

FreeFlightSimulation