The weapons feel unbalanced in proportion to each other. Bubbline is an odd weapon to start with; what I didn't like about it in the base game, being that Level 3 was hard to use for anything besides camping and had unreliable damage output, hasn't been changed. When I got the Fireball—sorry, Flircle (why was this changed and not the Bubbline? I dunno), I found myself almost exclusively using it, until I got the Vexor and never looked back. The Vexor is just broken: a piercing laser that has reasonable range, eats the projectiles that Mud Zone enemies have as their only defense, and can be spammed like the Polar Star? It really needed a cooldown at the very least.
The stage progression feels a bit stagnant compared to the original game. I often found myself feeling like I was encountering the same few enemies over and over again, just with minor additions now and there. For contrast, Cave Story often has unique enemies within the same level that are usually separated by section.
e.g. Grasstown starts out with Critters and Jellyfish, but they eventually disappear and give way to Mannons and the big frog enemy; Sand Zone is the more obvious example of groups of enemies being neatly separated for the sake of variety (Beetles in the beginning, Polishes and Sandcrocs in the top half, Skullheads and Crows in the bottom half, and a different variety of Crow in the bottom right). Snowtown starts with Bats and Critters, and ends with Bats, Critters, and Power Critters; Mud Zone starts with Skullheads and Crows and ends with Skullheads, Crows, Blue Skullheads that stay in place and shoot projectiles, and reskinned Flowercubs all sharing the same cramped tunnels. It's not a rigid structure, just something I've noticed: the stages in Defiant Hope feel longer despite appearing smaller.
The life capsules never felt like a challenge to get. When the original game had stuff like the Basil capsule in the beginning of Egg Corridor and the capsule in the ceiling in Grasstown that required environmental awareness as well as reflexes, it makes it feel like I'm just handed these health upgrades (not helped by the fact that Miya literally tells you how to get the capsule in the room with the fans and terminals—it's not even the first life capsule in the game, so it feels a little late for a tutorial). I could be biased in how easy the capsules were to get though, I have played Cave Story a lot.
I wasn't much of a fan of the bosses at all. The first two bosses were incredibly easy vanilla fare, though I guess they are the first bosses in the game, so I'll give it a pass. The next few bosses were also vanilla bosses I already knew like the back of my hand, except worse because the arenas were simplified. The "final" boss, even though it is completely custom, was completely static and had only one thing it could really do, and it got old quickly.
Something that kind of bugged me the whole way through way the dearth of custom enemies or mechanics. I can count them on one hand: the blue Skullhead, the drill boss, the Vexor, debatably all the cutscene animations starting in the mud zone... maybe this wouldn't stick out so much if this wasn't made in a custom engine. You could theoretically make anything you wanted, but I still just see critters everywhere.
I think the aspect of this demo that most obviously needs improvement has to be the story. Put simply: you're never really given a reason to care. Things just happen and you're along for the ride, which to be fair is how the original game starts out, but at least there things are built up, and you're slowly exposed to mysteries to think about, such as: "Who is this guy on the computer? Where is he? Who is Sue? Who is the Doctor? Why is he kidnapping Mimiga? How is this rabbit-thing Sue the sister of a human?"
In Defiant Hope, Miya takes a liking to the player immediately, and nobody seems to bring up anything about her other than that she yearns to see the world because... she's bored of being cooped up? The fact that her mom is dead, which seems like it might be an integral part of her upbringing and could have influenced her worldview in some interesting way, is only briefly brought up when looking at a generic picture frame in the background of her room. I hate to call her a Mary Sue, but I can't think of a bad bone in her body other than her being midly southern. Why does she have to emphasize her thankfulness to the player, as if she was being mean or something to make us doubt that she was grateful?
She gets along with everyone in a range of being mildly annoyed to straight-up friendly. The other main(?) characters aren't much better: Zun is diet King but without an actual justification for his distrustful disposition (you learn that King was very fond of Arthur, who the Doctor killed), while Ronnie is a twink who's good with tech and that's about it. Nobody else seems to be talking about them other than the soldier that attacks Ronnie, and you interact with them for probably five minutes max in the demo.
Even the player's origins aren't a well-kept secret: the intro literally opens with the player next to Booster, and Booster gives a whole speech to the player about the reason for their awakening, with the only mystery being a name that you inconveniently don't remember. The only thing here that's close to being compelling, and it's all speedran-through for the demo. And of course the demo ends with the girl that you've known for maybe half an hour being inconveniently killed by the Doctor replacement only ten or so minutes after making a big promise to her. This is like the equivalent of King not appearing in Cave Story until midway through the Sand Zone.
At least the graphics look pretty good. The stages are pretty and well-layered, the facepics are excellent, and the character sprites are mostly fitting, though there are a few NPC Mimiga that I remember looking spotty. The custom tracks are not all my taste, but what I've heard fits the scenes they play.
One more nitpick while I'm in here: Ivy's bitcrushed yawn really threw me off. Either voice effects need to be a little more common, or it should be replaced with a more chiptuney sound effect.
