Your pixel art looks amazing! I especially like the colors you've chosen, in the first screenshot it's just a few different shades of blue and sliver but it looks great.

Do you mind if I ask how you started out creating pixelart?

I really like the concept of this game, it kinda feels like the one of the ice maps from the old Pokemon games.

Positives:
- I liked the level complete animation when the blocks all fly away.
- I liked the trail that the main cube leaves behind but I think it may be slightly out of place. If the were made slightly more futuristic, I think the trail would fit in better.
- You've already got a lot of levels and the difficulty progression is pretty good.
- Controls and mechanics are solid.

Work:
- The background star image seems to be distorted in some areas, usually near the goal box. It looks black but instead of stars it has vertical white lines.
- The background could be made more interesting instead of just plain white stars. (I saw you mentioned this in your Upcoming Features)
- The colors of the blocks and the glow effect are a bit retro, not sure if that's what you're going for.

Cool game. I really like the music and the graphics. I only played a few levels of the demo and watched the video but it seems like the graphics are pretty repetitive. Are there plans to add more environments to the game?

Also, it was a bit hard to notice the text dialogues. I missed them in the first level and only started noticing them once got stuck and needed to hit the spacebar. Maybe add a sound cue or a bounce animation to direct attention to the text?

Looks like a cool game, it's a shame that you didn't continue working on it. Reminds me of a top down shooter version of Minecraft.

I think you've got the animation of the zombies down perfect. Some of the building textures look a bit blurry. I also liked the bloody explosion that comes up when hitting zombies but it may be a bit too bright and could be toned down.

Good:
- The game looks polished.
- I like the doodle art style, I think it's perfect for this type of children's game but I have some comments (see below)

Improvements:
- The green checkbox that flashes when you get a correct answer is way too quick. I understand that you want the user to be able to get back to seeing the main game screen as quickly as possible. Maybe you can have a smaller checkbox that appears near the bottom center.
- Going along with the last point, watch this video: https://www.youtube.com/watch?v=Fy0aCDmgnxg You need to make the user 'want' to be excited to win. Right now there is only a checkmark.
- The graphics look a bit dingy, kids are attracted to the bright and colorful. For example, the vertical stripes on the background on the main game screen is very unappealing. I think you can take some pointers from Doodle Jump and Tap Tap Revenge.

Cool game, reminds me of the ice caves in the original Pokemon games.

On my phone, Samsung Galaxy S5, there are black bars on the left and right side of the screen.

The controls felt a little cramped to me, I feel like you could create larger buttons and make them more transparent (so that you can still see the screen) or you could have a gestures where the user can swipe left, right, up and down any where on the screen but this may be a bit complicated.