Sorry if It sounded like I was pissy in my other comment..I was really super pissed off at the Catbird level...and especially after a fun boss fight like Smoker..a Touhou level is what I DIDN'T want. I have some OTHER criticisms with the game as well. But the biggest one thankfully was fixed with the addition of Checkpoints.
But the biggest one I have right now is that the Catbird Stage is WAAAAYYY too hard for being in the First world. It starts out fine but as soon as the first Worthog riding a Terodactyl is introduced all of the fun I have goes out the damn window as it basically turns into BULLET HELL, that I don't know how the hell one is supposed to Dodge without pouring HOURS into the game. I get the game is MEANT to be hard, I got that sort of vibe as early as the first level. But the difference is that the most of the levels were fair. If I wanted a Bullet hell Experiance, I'd play a Bullet Hell game such as Touhou or even Undertale.
To balance my complaining though I do have some suggestions as I mentioned in the other comment. One suggestion is nerfing the enemy's health, not to the point where they aren't a threat mind you..but rather to the point where you can take them out decently quickly without having to focus fire and get hit by other attacks in the process. Another Suggestion is making the Plane less of a pain in the butt to control, well..okay the plane controls would be fine if the level more focused on you dodging basic obstacles..but I'm assuming that's not your full intention. Honestly I feel the controls for it should be more like how it is when your spinning, and that ability should be more of a quick dodge in what ever direction you choose. It could end up putting you into a wall if you're not careful but at least it's SOMETHING for fighting the enemies in the level. And the Last suggestion is..honestly just scrap most of the enemies that fire at you in exchange for more obstacles, to teach the players how to control the plane as it is the first level with said plane in it...
Other than that..I overall enjoy this game for it's wacky Looney Tunes Humor, mixed with a simple yet..competent story over all and a really deep movement system that encourages you to be creative with how you go through certain levels. Not to mention the Boss fights so far are fairly on point with little to no problems as far as I can tell. And I do hope you continue working on this as it is overall a good package so far. Though one last suggestion, please add controller support..a controller would be amazing for a game like this.