The Castle Wars app is ideal if you're trying to get a trimmed completionist's cape. The clock is always synced to the Castle Wars games in world 24. You can set several different alarms at crucial points in the game such as 4:30 before the game end.
Simply select the at what times in the game you want an alarm to go off at the top two rows, then select what sound every alarm should make. (beep or/and voice)
Note that the ingame timer is always rounded up this means that an actual time as 16:12 would be rounded up to 17 in game!
Also: this timer is synchronized to the world 24 games and not usable in any other world.
