A glitch I've noticed whilst playing (read: spamming) combat events.
When there's a -lot- going on on screen, fired weapons sometimes appear invisible. Most noticeably it's causing invisible plasma bolts and missiles, although the charge effect for the plasma still plays and the spiral trail effect of the missile still shows up too. The weapons themselves still work, but just turn invisible. Sometimes when firing rockets only the central rocket is visible too (I assume the left and right rockets are still there).
This is really easy to reproduce when playing Combat on Downtown due to the abundance of triple-stacked weapon pads on multiple parts of the circuit.
I've also noticed that being hit by a quake whilst going over a pad means you don't pick it up (probably being too high from the track) despite the graphics of the pad raising up with the track. Not sure if intentional or not.