It ain't bad but...it's not that great either? Basically, the game reminds me very much of those memes where they're like "that game sure was a game" or something akin to that, haha.
Again, it's not a bad game, heck, I'd even say it's a good game. Certainly does make a good impression with its cute intro, and overall the game has a solid sense of craft to it in all respects: graphics, sound, music and retro aesthetic. Couldn't see any major complaints with the movement or anything either, other than it was a little confusing that the bounce you get from an enemy goes higher than the bounce from a box (maybe you shouldn't even bounce that much from a box in the first place, if at all). So yeah, all in all, it was good.
But in general, while it was "good," I just found the game to be very plain and bog-standard, and therefore not very fun. It pretty much just felt like a basic platformer or Mario clone without any unique mechanics or ideas of its own, leading me to questioning why I should even bother playing it. Not only did it not seem to have a hook or anything like that, the game was also in general very unchallenging and thus not very engaging, and any bonuses to strive for that might've engaged such as those big stars were both very simple to get and ultimately pointless as I was unsure what their purpose was.
There are also some slight bugs like how you can fire the weapons as fast as you can press the button: feel like that should be limited to a locked fire rate, otherwise it is an unfair advantage for people with faster fingers to cheese certain parts of the game by absolutely blasting them away.
Might just be a case of the game being a slow burn: the bonus level does showcase some more challenging late game levels that we might see in a full release, but even then the overly simple movement and lack of juicy effects or some sort of unique style made it still feel less than impressive. Furthermore, even if the game is a slow burn, I'd still argue that the game should step up the pace and hook us with something early to keep us interested and all that, but despite my complaints, I am looking forward to seeing the final version of this eventually since it is promising and shows effort, so best of luck!