In May 2018 I flew with KLM from Singapore to Bali. Changi Airport is one of the few airports that has no barrier between arrival and departure gates. When leaving the aircraft, arriving passengers will be mixed with people heading for their departure gates.
Security checks are done directly at the gate.
I really liked the open atmosphere as normally you would be channelled through some narrow hallways until immigration and security check are completed.
Singapore Airport has an opposite concept and I would fully recommend this airport when arriving or transferring to other flights.