The fuck is a planktid?
On the one hand, Luminesca is explicitly early in development. Only two of a planned five chapters are currently available, and if you look at some early videos, you can see how dramatically the game design has changed already. On the other hand, even for having a presumed 40% of its content, there's very little here: each current chapter lasts only a few minutes, and there's barely a hint of challenge, or even intrigue, in either of them. The gameplay mechanics are extremely shallow -- you can move in two dimensions, and you can shine a light in an arbitrary direction, which occasionally activates an item. Sometimes you have to lead a glowing "planktid" toward a switch, guiding it through parts of the level. It's all remedial stuff.
What Luminesca has going for it, though, is its beautiful style - think a more pleasant, but still dark, version of Insanely Twisted Shadow Planet - and how generally relaxing it is. More so than Aquaria or even Ecco the Dolphin, Luminesca's soothing underwater atmosphere has no real trace of stress or strife. Again, this is arguably a bad thing in terms of the game's interactivity, but it makes for an agreeable lazy afternoon activity.
Better than: Dear Esther
Not as good as: Unmechanical
Of course: I'll still plan to revisit the game when it's more complete.
Progress: Finished Chapter 2.