So, I played your prototype, and died at about 45% completion. But, you need better feedback than that. So, here I go.
What Worked
The mix of platforming and tower defense mechanics is a good one - it took an otherwise ‘done’ idea and breathed new life into it. As this concept is the main conceit of your game, it says good things about your game, even as a prototype.
The tutorials were useful (they could’ve been presented more expertly, but I’ll get to that.) I was never in any question about what to do with any given artifact in the game. Further, I’m assuming you took some lessons from ExtraCreditz, particularly their design club on World 1-1; you used the concepts from Super Mario Brothers to start the tutorial level off effectively and efficiently. You kept those concepts in your prototype level, as well.
What Didn’t Work
First things first - your opening still-image cutscene was wonky. I didn’t know what to press to advance the dialogue. In the end, it partially turned out to be your webpage absorbing my pressing Space, and I had to re-click in the webplayer to get it to properly absorb inputs again. But, it was irritating. It would be a good idea to have an indicator on what to press to advance the dialogue; I actually considered giving up and griping right then and there, if I couldn’t find a way to advance it. Luckily, I did.
Next, your audio - I love Mega Man X as much as the next gamer, but the audio balance was off. Now, this gets a bit tricky - what you find pleasing, is what another gamer will find completely wrong. You really need some way to let the player modify their audio settings - master volume, music volume, and SFX volume are the mandatories. Let players set the volume to what they like, and audio balance will pretty much become a non-issue. It’s a small thing that you can do to really help your players’ experience.
Next, your tutorials. While they were effective, I’m a seasoned gamer. Unlike World 1-1 in Super Mario Bros, you have an enemy that appears in a fixed location, no matter what, that if you take too long figuring out the controls, will be on top of you before you can do anything about it. To solve this, I would create a trigger that, when entered, spawns that first enemy, then self-destructs, to recreate the ‘First Encounter with Goomba’ experience - you want players to face their first enemy only when they’re ready to.
Still on the subject of tutorials, consider replacing the text that appears in the level, with a graphic that immediately conveys what the player has to do. Instead of “Press Space to Jump”, have your three-block-tall wall, with some graffiti with a space bar and an up arrow. Simple pattern recognition will let players reason for themselves, “oh…I have to press Space to jump!” It will be easier to blend into the game environment, without breaking suspension of disbelief.
Similarly on the subject of tutorials, when the cannon that must be defended is introduced, you’ve got two powerups that must be slammed towards the cannon - the POW bubble and the Heart bubble. Instead of having static text telling the player with words what to do, you really should leverage your mechanics and conventions. The cannon and the player will always be going from left to right; thus, a left-pointing arrow on the POW and Heart bubbles will naturally tell the player, “You need to make this go this direction to help the cannon survive/power up.”
Last thing on the subject of tutorials - when you do use text, do check your grammar. There was a message that read like it came out of Zero Wing or something. Nothing makes your game look inexpert like bad grammar, or lack of consistency of assets.
The controls themselves to me felt a bit ‘loose’, and this was a problem, because it made the character hard to control. I’d consider slightly reducing the player’s movement speed. Also, I had a hard time gauging the player’s jump height relative to the tiles you’re using, which is a problem - one of the benefits of using tiles in the first place is giving players a ‘measuring stick’ to plan solutions to movement problems (e.g. jumping.) Thus, it makes great sense for your player’s jump height to correspond to a number of tiles. You can see how I did it in The Hero’s Journey - while some of the jumps are a bit on the contrived side, you’ll find yourself able to make them every time, if you can make them.
Similarly, the player’s melee attack range is far greater than that of the animation. This is a problem particularly in the tutorial level when you have to jump and attack in order to clear the increasing block towers. I wound up doing it, but it was very wonky and unsatisfying.
The Space/Z to recover energy mechanic also does not work. When the character was recovering HP, I tried practically spamming Space/Z, but nothing appeared to happen beyond the automatic regeneration. You’ll want to look into this, or nix it in favor of enemies dropping energy cells more frequently, and energy cells being a consideration in your level design (harder difficulty would just increase the gaps between energy cells.)
The POW and Health bubbles in my opinion would benefit from just going to to the cannon on collision, as pickups, instead of having to hit them to the cannon; as the level got more frantic, I found myself having to skip pickups, because I had other concerns (smiting foes.)
The flying enemies that carry wood in the ‘primary’ level of this prototype were a problem - they came in so high, even the ridiculous jump height on the character couldn’t help me reach them, and were a main part of why I couldn’t finish the stage.
The TL;DR
You’ve got a good concept for a refreshing take on the platformer, but you’ve got a lot of opportunities for improvement in both presentation and tuning.