This is a good start to a potentially great game! Pac-Man was one of the first video games I ever played and understood, so it warms my heart to see someone trying to mix up the old formula.
Here are 2 ways I think you could further develop this game: 1) turn it into a story-based game, with a campaign that rests on the mechanics presented in this demo; 2) an intense action-packed arcade-style game. With 1, you would want to have story interludes between each level that sets the stage for the gameplay. you would then present the player with unique objectives for each level and let the player figure it out. With this method, you would need to tweak each level so there is some new wrinkle on the core gameplay that poses a unique challenge, such as avoiding the orcas entirely for a while or transforming a certain number of times. With 2, you would want to make the maps (at least the initial ones) smaller and introduce each gameplay mechanic slowly. You could have a tutorial section before each level for the first few levels to show how each mechanic works and then give the player a map that emphasizes using just those mechanics. As levels progress, more and more mechanics are layered on until the full experience is in play, and then it's just a matter of making variations on the maps. Of course, these are just the things I came up with as I'm playing and may not be your ultimate vision. If you don't do either of them, I might just have to make them myself because you've inspired me! 😄
Now for the critical analysis: I do not like the control the way it's set up right now. Having to maneuver my pinky on the shift key while my other fingers are occupied with moving was not pleasant, especially when I have a whole other hand to utilize. I highly recommend implementing an input customization option if you can. I do appreciate that the controls were explained on the game's page and that it's not too complicated.
The maps are very same-y. I'd like to see not only different tile sets, but there should also be some distinguishing features that make each map unique. Maybe instead of having the cannon balls crashing down on every map, make that a feature of just one of the maps. On another map, have a different unique mechanic, like pressing a combination of buttons obliterates all whales in the area.
I enjoyed the dash and transformation mechanics. The dash is intuitive and has a good area of effect, and the transformation feels like a true upgrade. The current objective of purifying all of the tendrils while transformed feels a bit overwhelming, but that could just be due to the current state of the game. It would be better if the initial maps were smaller to give the player a better chance of getting the idea and feeling accomplished.
I enjoyed this game overall even in its current state. I hope you continue to develop this game whether you take my advice or not because it's a good start!