A swarm of glowing jellyfish hangs above the seabed. Slide your little bathysphere left and right along the bottom: drag anywhere on a touch screen, move the mouse, or use ← / → (or A / D). It fires all the time, with at most 2 darts in the water at once, so line up your shots: a dart that misses has to leave the screen before you get it back.
Jellies of one colour that touch are threaded together into a group. Every few seconds some jellies leave the swarm and dive at you in sweeping arcs, each trailing a thread back to its group.
Where you hit a diver decides what it sets off. Up high, it bursts alone. In the middle it takes one neighbour with it. Below the glow line near the bottom, a pulse runs up its thread and bursts its whole group. Rings show what a hit would set off right now. The best play is to slip out of a diver's way and hit it late, if you dare.
Jellies in the swarm have a shell, so the first hit only cracks it. Divers burst in one hit. Queens (gold crown) take 2 hits and dive with escorts. Stingers (red barbs) drop sting darts. From wave 11, Armoured jellies take 2 hits even when diving, Darters dive fast and Weavers zigzag. A pulse bursts them all.
A diver or a red sting dart costs one of your 3 lives. If the swarm sinks all the way to the glow line, everything dives at once.
The waves never stop. When a swarm is cleared, the next one slides straight in, a little harder each time, up to wave 99. Every 10 waves cleared earns a life (up to 5).
Scoring: in the swarm, Drifter 50, Stinger 80, Weaver and Darter 100, Armoured 120, Queen 150; divers are worth double. In a pulse, each jelly scores its diving value times its place in the pulse (1st ×1, 2nd ×2 …), so a whole group of six Drifters is worth 2,100. Every wave cleared adds 500 + 100 × the wave number.
On a computer: P pauses, M mutes, Enter starts.
