Whilst I've seem this concept done before in Blitz Breaker, this game clearly has enough of it's own charm to still stand out.
Starting with what little story there is, it was quite charming, though I do have a couple of nitpicks. For starters, the writing fairly bland and under-characterized which makes me wounder why it's even there in the first place, the game really doesn't need it. Secondly, I get what you were going for with the "same thing happens every time" story but it just gets dull after a while, it would have been nice to see it subverted more or having the trails Mr Dashington faces be taken to a ridiculous degree. I know story isn't the focus of this kind of game but it's still a part of the game and it could have been improved without needing to add any more focus to it than already exists. The flying fish at least did somewhat hit upon this which was nice.
As for the menus, they're quite nice and I like the feel of the buttons, the whole "buttons being actual buttons" thing is always quite appealing. Couple of issues though. Firstly, having the SFX icon be a speaker is very unclear, saw it and assumed it was a master volume button. Secondly, having the music auto stop when I'm paused would really help, particularly when writing this review. Finally, if Escape is the pause button please tell the player. I'm always scared to press it encase the game closes or something.
On to what matters most, the gameplay. As I implied earlier, it's very good. Not only are the core mechanics solid, each level mechanic manages to build on/compliment it. You can clearly see that everything in the game is designed around this one idea. Most level mechanics are well done as well, there's quite a variety and they're merged together where appropriate to make things interesting. I do think that the sine wave patterns on some of the mechanics such as the spears was awkward but it didn't ruin them. The only mechanic that really stood out as bad was the rising water. With the running water it made sense I couldn't dash horizontally because I was already moving that way and that really added something, but here, having to keep dashing up to dash left/right was so tedious. However, giving how many mechanics you use it doesn't overstay it's welcome.
The different areas were a little generic in their theme, but each one managed to stand out from each other and the mechanics did a good job of building on top of the themes.
Only thing that's left is a few nitpicks:
-The periodic screenshake made me feel sick after a while
-I think a smaller sprite would have worked better to give more leniency in some parts
-Occasional secrets would have helped vary the pace
-The bottomless/s could have been signposted, though it's still fairly clear which path is correct so I suppose it's not a big issue
Overall, whilst it feels a bit shallow in places there's no denying it was fun and the mechanics are executed well.