The game becomes impossible to continue playing without payment.
"You can revive once by run (seems there is a daily limit of revives however), by watching an ad, or spending premium currency (15 gems). You can play more by refilling energy (or waiting)"
"sometimes you basically cant play the events without paying because sometimes more expensive event registeration has tickets that you cant get without paying or takes a really long time to grind for and most of the time the cheaper registeration is not worth playing and has really bad rates"
"When you run out of items a pop up appears prompting you to buy more."
"Later routes (particularly Another Story) cost more hourglasses than the player is likely to receive through gameplay alone."
"At one point in the game, the cgs that the characters send don't load any longer unless you pay for the subscription and "upgrade" the antennae. it doesn't keep you from making choices in the game, but it does force you to choose blindly since you can't see the photos anymore."
"either grind a long time for daily diamonds or pay to get better trainers to fight higher level people"
"The Crucible. Destiny's PVP equivalent for Casual and Ranked play are gated behind Whatever current expansion is in an attempt to curb cheating and exploitation. A $10USD Dungeon key bars players from access when Dungeon were once expected Free."