Changes
/* Rewind feature */
ACE-DL has a rewind feature, but it is not as good as it could be: [https://youtu.be/wIKGvpnJLUo Demonstration of rewind in ACE-DL]
A very simple approach would be to make a SNA for each frame and limit the RAM snapshot to 128KB, which is ok for 99% of CPC software. For a 10-seconds long rewind functionality, only 64MB RAM is needed (128KB * 50 frames * 10 seconds).