After Burst for Game Boy was released Japan-exclusively by NCS in 1990. Conceptually just a simple 2D shooter it features three modes (normal, 1P VS, 2P VS) of which this run plays the 1P VS mode. To reach this mode's ending, 15 (instead of 30 in normal mode) single-screen stages have to be cleared (all of which are different from the ones in normal mode).
The game features a ballistic bullet mechanic where you can charge each shot to have a higher exit velocity. Since only one player bullet can be visible at a time, the damage that can be done in any given timespan is severely limited, necessitating hitting multiple targets in one shot for best efficiency.
Quite strikingly, this game is plagued by extreme lag, slowing in-game time down significantly and contributing to about 80% runtime of the entire movie (about 4 lag frames per normal frame).
jlun2 improves the previous TAS by 7.74 seconds, thanks to decreasing the downtime between shots by changing their aim.