Hi, thanks for playing my game :D This was the first game I ever made, for a week long game jam where plugins were banned and we were limited to only RTP assets and minor self-edits of RTP. Maybe you could give it a rating? I'd appreciate it :D
As for how this works, I wrote a post detailing it in this thread: https://forums.rpgmakerweb.com/index.php?threads/luke-daimont-absolute-mayhem.12... , so check it out if you want. The only thing that's changed in the latest version is that instead of a dedicated parallel event for the projectile hit detection for all the enemy events (and thus the necessity of adding a conditional branch for each and every enemy event, which took hours), each enemy is instead a parallel event that constantly compares its position to the position of the projectile event. Doing it that way is more CPU intensive, but much faster. Currently trying to figure out a better way. If you have more questions, feel free to ask. :)
Btw, if you like more action/arcade games made in RPG Maker, you should probably check out my other games. Especially End of Winter might be of interest to you :)