All advice duly noted! And some questions answered:
There are no enemy crits in the game; when the shark boss did 100 damage to you, it was because he'd inflicted his Defense Down status effect on you first. Stunning him or defending after he used Rip Armor would have prevented you from taking crazy damage.
Battle system is 90% Atoa's chrono trigger battle system, though I edited a lot of parts of it and added a number of things.
The tilesets look weird because they're 70% pixel graphics and 30% photographs. It's a noticable problem in parts of the shark factory. The unpleasantness of fixing things like that is a big part of why the game is only getting updated at 10% of the speed I'd like.
Thanks SO MUCH for doing this video, you have a very useful perspective and this was really helpful. Plus, it's just super fun for me to watch people enjoying the game.