Despite being unsampled, I was wondering how did you achieved this sound at channel 3 (channel 4 in the SPC player) at 0:05.
(!100)[@6 with zero attack and infinite release]
(!101)[@7 with zero attack and infinite release]
(!100, -1) plays when immediately keyed in. @6 resembles @7 the most while having zero differences in the beginning of the sample and loop points.
(!101, 1, 192 or =1) plays immediately after one tick. This is because @7's sample has some noticeable attack in the sample compared its sustaining loop point. Sample's playback position doesn't change when the sample changes itself while the note still sustains.