Ambitious piece to undertake!
Piece is improving, but I want to point out that approaching pieces of art with this kind of "make it up as you go" approach will cause endless headaches for you, and ultimately make art that doesn't meet its full potential. Plan pieces from the outset. There's little apparent thought gone into the composition. It seems more like a bunch of different items dropped in together. Just something to keep in mind.
There's no real shading in the piece. Each object basically just appears as it would if there was a completely uniform white light, or is very minorly shaded independent of the rest of the picture (compare the shading of the bucket to the balloon to the umbrella). To put it another way, everything is coloured, but not shaded. It's a near-flat value image. The balloon's specular implies a near midday sun as the lightsource, which I think matches the setting. You need to decide on a lightsource and really bring out the lit and shadowed parts of the picture.
Perspective is arbitrary throughout the image. The bottom right is isometric, immediately above it seems to be a non-oblique pespective for the shoreline (it looks far away because of how small it is), it's like the umbrella and chairs are at the top of a dune and the shore is farther away at the bottom of it and the slope follows our line of sight. Horizon is an oblique front-view perspective. All of this gives a sense of flatness, and combined with the arbitrary composition leads to a complete break in the punch of the piece.
The way you have lightened some buildings in the city is also arbitrary. The reason buildings get lighter and closer to the sky colour is because of "aerial perspective". It's because the further away something gets from the eye, the more atmosphere/air the light has to travel through to reach the eye, and the more scattered it becomes, changing its colour and contrast. I think that's the physical explanation, anyway. All you need to know is, the further away something is, the closer it gets to the sky colour. You currently have some buildings which are nearer that are lighter than buildings further away, which looks bizarre.
I assume that's lightning coming from the cloud? If so, I say remove it. It's entirely inconsistent with the rest of the setting. A bright, clear day at the beach, with a single cloud in the sky casting lightning?
Still a lot of broken line noisiness (shoreline, for instance). I'd say at this stage of your pixelling, keep it a basic rule to have your lines unbroken. Broken lines create a lot of isolated pixel clusters in noisy patterns, and AA isn't really the way to solve that.
Best of luck
