I'd greatly aid learning if there was a way to record, replay and download my games. Replaying downloaded games might require a separate app, previously downloaded and running on the users machine. That's ok. If the game is replayed on the server, the app could be running on the server. Replaying also needs some features, like stopping at a
particular move, and being able to step forward and backward a set number of moves
(usually this will be one, but in some cases, we may wish to skip a sequence of moves).
To supplement a player's memory (it could be done with paper and pencil, but tediously),
the replay should enable a player to stop the replay and query for any piece, where in the opponent's setup it came from, and if it's ever been revealed, what its rank is (player may forget or get confused about which piece it is). The ranks of pieces not revealed in the game should not be part of the game data file (the opponent's data file will be a different recording of the game with showing the ranks of his pieces, but not yours), so it can't be used to scout the other player's setup beyond what was revealed in the game. It's also be useful to be able to add/delete/edit annotations to the file associated with a move so I can save evaluations, for example. The speed of replay might need to be adjustable, because some games are too slow or too fast. The game clock won't matter on replay, so replay could be timed one move
every 3 seconds for example. Sir Richard