Hi! I like your Tower Defender. The low-poly is a good choice, and overall, it looks like an excellent base for further development. I played in Safari, and it worked, although not without some lags. So, I will comment on the web version.

The tutorial is a great idea. It feels so much better when a game invites you to play with a simple due course explanation.

The only problem with the keys I had is that the Shift button is also highlighted in the tutorial popover. But at the same it does nothing. I thought it was for running, but it didn’t work and left me wondering if it was a problem with the browser version or something else.

In general, there was still some “what shall I do?” feeling. But it was super minor. Maybe you can consider placing a preinstalled tower and letting the player see how it works and what the goal of the game is. Then, build the second.

I played without a gamepad, which is why, at first, I could understand the “A” and “B” buttons being shown here and there. At first, I thought they had some gameplay meaning.

For some reason, the tower menus weren’t so intuitive. But how their stats are presented and the set of choices you have to look good and really helps.

At some point, the tutorial seemed to stop. No more fishermen were coming, and I couldn’t build more towers. I could walk arround though. Maybe it was the end of the demo? Or maybe it is a bug?

Seems like you already have a decent foundation for a tower defense. I tried it on web and Windows. The web version definitely has some oddities (which you seem aware of), but I didn't experience any issues with the Windows version.

Tutorial:
- I think it's okay, definitely would be better if it was more reactive. My only issue with it was having me try to build a tower and then telling me I need money to do it. I think the concept is common enough that you can just have the player pick up the money and immediately build the tower.
- I don't know how much faith I'd put in playtester's claiming that Esc for pause menu isn't intuitive, that's been a staple of game design for 30+ years. Maybe for someone unfamiliar with PC gaming that would be odd, but it's the industry standard, so don't waste time worrying about that.

Feedback:
- The main menu was not clear, in my opinion, as I didn't realize there were game modes other than Tutorial on my first 2 times loading the game.
- The flying fish on the last round of story mode taking a different route felt a bit unfair. I don't think there was any indication that enemies could come from a different spawn, and I didn't have sufficient defense or money to stop all of them.
- I do think the theming is a little odd at this point, having an arrow and cannon tower next to a missile launcher feels a little odd. Nothing wrong with it this early on, but I'd like to see unique, thematic towers as the game progresses.

The first wave (OF ENEMIES!!!) spawns before the Ballista is built, therefore they can proceed on their way and won't be defeated. Because of this, the sequence of Tutorial lesson will break and not be able to pass further. 

The visuals are great I like it's style. Audio is not bad either but could use some more effects for certain events (maybe upgrading a tower, fish dieing, wave round starting, etc). The UI is pretty good except some thing felt a little buggy on KB/M like upgrading the towers, I think the functionality probably was more intuitive on gamepad. One suggestion is that at the start of the stage maybe show a visual path of where the enemies come from or go, or like a minimap/high level overview.

One issue I encountered was frame drops/stutters and performance issues at certain stages throughout the game, I wonder if there's some un-optimized code causing issues?

Nice work