The following are known Action Replay Codes for Shamus on Nintendo Game Boy / Color (GB / GBC). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark

Infinite Lives
01636edc

Enable Key Display
01016DDC

Have Key 1
010165DC

Have Key 2
010166DC

Have Key 3
010167DC

Have Key 4
010168DC

Have Key 5
010169DC

Have Key 6
01016ADC

Have Key 7
01016BDC

Have Key 8
01016CDC