The main hook that separates Lucid from the plethora of countless other falling block puzzle games is the way you remove these blocks. Rather than guiding pieces through mid air to try perfectly filling in empty spaces or position them so they match with their similiars, here the board is already full and you have to use your best judgement to trace a line through blocks of the same colour to remove them from play and send all the pieces above them crashing downwards. Remove the required colour and minimum target number to fill a circular gauge at the side of the screen, the more blocks you remove each turn the greater the amount the gauge will fill up and complete the stage. But there's a catch, as there always is.
While the minimum allowable number of blocks that can be removed in a single action can be as little as two, and with the upper limit only being whatever's actually available, if you want to remove a group of matching blocks then you MUST be able to remove all of the ones that connect to each other in that one action. Also, the line you trace has to be in a single, continuous strand that cannot cross over or repeat back on itself. So, for example, a T-shaped arrangement of blocks could never be removed because, after the starting point, the line you draw would have to move to one side or the other but then could not reach the remaining blocks without going back over itself and therefore could not connect all blocks of the same colour. It sounds kinda complicated, but trust me, it's a lot easier in practice.
There are 55 stages in total, and at first it seems like each one is simply a random collection of mixed colours that you remove with little thought, but you then begin to realise that the field of play isn't as haphazardly laid out as it first appears and there's actually an art to planning ahead and setting up the blocks to maximise your score and finish the stage more quickly. You can still randomly draw away at groups on a whim for the most part, but in later stages you can easily lead yourself into a dead end with no more viable options as the clusters of colours form shapes that are all but impossible to remove.
Unfortunately there's a fly in the ointment, though it isn't so much the way it plays, but rather, everything else. The presentation is mostly passable, but you can't shake the sense that there's something of a cheap or unfinished quality to it, as if nothing about it feels... "solid", like there's a very unsatisfying disconnect between the player and everything you interact with. It's almost like the cursor is hovering over a sheet of glass the entire time and never really touching what's on the other side. This would seem to suggest it started off life as a tablet game (where it would be perfectly suited), but apparently this isn't the case.
This isn't a bad game, by any means, but with its lacklustre feel and complete absence of any additional game modes beyond the 55 stages on offer, what could have been a really great game instead, frustratingly, is only a good one for casual puzzle fans to enjoy.