Bleach:Zanpakutou Senshi is a totally free Total Conversation of Half-Life 1. It´s based on the japanese hit Anime Bleach.
15.75 -> 16 shots per second.
The gaps between the spheres appears to be around the player size and the worst case scenario of 32 players shooting at the same time keeps the amount of entities down at 512 - (1200 is max, 1000 prefered max).
Based on the velocity being normalized to 1000 and the players maximum speed being 1/4 or 250 - then per frame(60 fps) a collision box would travel 16 units and the player would travel 4.
This means that we can have a gap between 32 units (player size) and 44 units (32 + 16 - 4) and a collision is ensured to be within frame 1(16ms) or 2(32ms). The player's acceleration and de acceleration won't be high enough to play an important role - the player will only be able to evade it if that was the initial intention and 1 frame is an acceptable loss, also considering the extremely narrow possibility of fitting between 32 and 44 dead ray for 16 ms.
The goal is to make this look like the 60fps example by replacing the sprite (just like ESF who use the tail sprite for their beams) and have it cover the collision box and the gap till the next element.
Ah... all that engineering and math there is in game development :)