The impasse from exactly 2 years ago (the last comment) was pushing the block that looked like a regular wall in the center of the room in this video at 5:51 in the walkthrough https://www.youtube.com/watch?v=rzl190B7KN4. That was the missing key to it, not trying to move that block because why would you when you've already run into so many and they could never be moved before. It would probably have been better if that block had been made a different color slightly or shaded somehow differently, or somehow else made to look different, like how the ones that can be blown up with 3 superbombs are shown with a crack in them, or if moving such a block was the requirement for getting another easter egg/secret and not a requirement for actually proceeding in the game.
This is the best indy game of its kind, simple or should I say minimalist adventure games made from the bottom up, where the graphics are secondary to what they represent. It really reminded me of Atari 2600's Adventure. Robot Wants Kitty is a close second if you want to call it that. I'm sure you engineered everything yourself in the tiniest detail, including for instance how when you press a directional button you immediately go one space in that direction, then there's a time delay while you hold it, and then you rapidly proceed in that direction. Which also causes some problems on its own right. The only effective way to travel relatively short distances, like 4 and exactly 4 spaces not 3 or 5 or all the way across the screen, is to hit the directional button 4 times instead of holding it down because then you'll probably be off by 1 or even 2, and on my computer, it makes playing it too much potentially an adventure in carpel tunnel syndrome. Maybe you could have had the arrow keys be one-shots, you press it down and it goes one space immediately and NEVER starts going fast no matter how long you hold it down, but have the awdx keys IMMEDIATELY start going fast as you hold them down, the way it does only after holding down the arrow keys after several seconds as it is now, so there would be 8 directional control buttons, one that works like a machine gun and one that works like a pistol if you only want go one space and fine-tune your motions. I don't think that would be too complicated, z is bomb so it doesn't interfere with awdx and then there's the space and m for menu and that's it, 11 total buttons.
It has everything in the right balance other than that one bit of deception with the block you have to move which is too dependent on luck in discovering it as an event to allow proceeding, I think. It's the right duration for a sane attention span, not too simplistic nor too drawn out, the puzzles require care and attention but not to a daunting and extremely unpleasant degree, the bosses are classic bosses with methods of beating them. And set to memorable midi latin music. It's like a revisitation to Atari's Adventure combined with a few other games from the 1980s. Though Adventure was the 70s. Games I played in the 80s. The one way it could be better is if like Adventure, there was a way to somewhat randomize item and monster locations so it wasn't the same exact game every time. I guess the random element of the wandering monster motions make it not exactly the same game but other than that it is. My best A+ rank 0-death speedrun is 22:39 but I see someone on youtube has it up in under 20 minutes. It probably depends on the keyboard you're using, mine is awful, it has the up and down buttons RIGHT next to each other and each one is half the height of a regular keyboard key, and the right and left buttons way to the side of them so pressing them down over and over quickly is not fun.