Xbox player here. I won't mention MK1 and MK2 issues as they've already been reported better than I could have.
Ultimate Mortal Kombat 3
* Secret characters in UMK3 didn't stay unlocked for me after turning the game off.
* Did an animality twice before getting the achievement. First time could have been a glitch, as I appeared to complete the move after the character had fallen.
* As mentioned by many others, sound issues, especially low volume music to the point it seems non-existent.
* Inputs occasionally lag when looking up a move (but not always)
General Arcade Kollection Issues -
* I got the achievement for beating UMK3 (right away), but not for completing all 3 games. Letting the credits roll to the end of UMK3 didn't work.
* As mentioned by others, default brightness seems too high and is not customizable in game.
* In the Xbox menu, Arcade Kollection uses the MK2011 artwork instead of having its own.
Ultimate Mortal Kombat 3
* Secret characters in UMK3 didn't stay unlocked for me after turning the game off.
* Did an animality twice before getting the achievement. First time could have been a glitch, as I appeared to complete the move after the character had fallen.
* As mentioned by many others, sound issues, especially low volume music to the point it seems non-existent.
* Inputs occasionally lag when looking up a move (but not always)
General Arcade Kollection Issues -
* I got the achievement for beating UMK3 (right away), but not for completing all 3 games. Letting the credits roll to the end of UMK3 didn't work.
* As mentioned by others, default brightness seems too high and is not customizable in game.
* In the Xbox menu, Arcade Kollection uses the MK2011 artwork instead of having its own.