This has the potential to be really fun! A trail effect on the dot would elevate the visuals greatly. Sound would also improve this infinitely, right now it's a very sterile game.
Something that I haven't seen anyone else mention: There is a 30 second timer in the top right corner that doesn't indicate anything. The dot will die when it's ready to die, regardless of how much time there is left on that timer. Something showing how much time the sound wave has left to live (quick thoughts: the length of the trail once it's added. The color going from green to yellow to red. The sound getting quieter. An accurate timer).
Besides the (lack of) sound, an even greater issue with the game is the level intro screen. The fact that the player has to wait roughly 2 seconds after resetting (something that also should happen on it's own a short time after the dot dies).
Level 8 is incredibly clever! Not only does level itself shows us the direction we're expected to go, even our own tools fool us. It felt really nice once I got it. Love it! I'd honestly put it last, but I understand it's earlier placement because it's probably the best one in the game.
Level 2 and level 4 are exactly the same. The only difference is the presence of a gray block vs a pillow. Level 2 is all about teaching us how the dynamite works. Having the same level twice with such a small difference is mean to teach the player that the pillow absorbs, and the wall bounces. This is necessary info for Level 10. But the player knows that dynamite blows up things that are in the way. They will not try to see what the pillow does, they will place the dynamite in the exact same place and never see the wave touch the pillow. In the context of the levels both the block and the pillow do the same thing: they prevent the player from winning by blocking the way.
As for level 10, I get that the idea is for the player to try to blow up the pillow, but not having the pillow there gives the exact same effect as having it there. In fact I can't really think of any reason where having a pillow would be necessary. Oh wait, there is one. If there was a pillow blocking a wall you need to bounce off of, you would have to blow the pillow up.
This is such a short and sweet game though and it makes me a bit sad seeing that it hasn't breached 10 rates yet, it's good! It's just the right scope and size and gameplay style for a web build, which would probably have given it the attention it deserves.