About the APK build

What it is: the Android build of the original Five Nights at Freddy's
Contents: the full game, not a demo - nights 1-5, night 6 and the custom night
Controls: touch - tap the camera panel, the doors and the hall lights
Connection: none needed once it is installed
Prefer no install? the browser version is on the FNAF 1 page

The Android version of Freddy 1 is the same game that made the series, squeezed onto a phone screen. You are the night guard at Freddy Fazbear's Pizza, working midnight to 6 AM, with a camera panel, two doors, two hall lights and one battery shared between all of them.

What changes on a phone

The door buttons sit at the screen edges, so both thumbs stay busy
The camera panel is pulled up from the bottom rather than moused over
Audio cues matter even more, because a phone speaker flattens direction - use headphones
Everything else - the AI, the power drain, the endings - is untouched from the PC release

And remember, he always comes back.

If you want the story that follows on from this one, FNAF 2 is the prequel and FNAF 3 jumps thirty years forward.