First off, this game has some fantastic pixel art. The effects like the jetpack stand out in particular. I do have some issues with how the art can interfere with gameplay. Platforming in a tight area can be quite annoying (admittedly this may be more of a pico 8 issue) but it's even more of an issue with the 3d look the grounds got going. I could point out where the robot would land if asked, but in moment to moment gameplay it can make platforming feel quite awkward.
Furthermore some things don't convey what they do very well. Like the enemies are all vague things. One's a bolt that I ran into at first because it doesn't look like an enemy. The green flying thing looks more like a collectable than an enemy. The lightbulbs look like something I'm meant to shoot but are just environment.
Onto gameplay
I think having the bar deplete from the start is quite confusing since it just sits at empty and seemingly has no consequence, that left me confused.
As for the whole main mechanic of switching, I think it's the game's biggest issue. For starters I rarely notice when I've changed. This is made worse by the fact that I couldn't tell what exactly was depleting it.
But just as a whole I don't think it adds anything, it's more of a nuisance than anything. Each lasts sound short there's no point really getting used to it, shooting just becomes more cumbersome. In something like Megaman, the different powerups mean there's some tactics to which one you use at which point. " In games with multiple power ups, often the player sticks to one power, either because it's their favorite, or because you just forget about it." I don't think the solution to this was to remove all strategy. I'm left feeling like the game would be better without it, it's just a gimmick. I'm still just going to run through and shoot everything so it doesn't add anything to the experience. "the player is incentive to use all powers and mobility options." No, no they're not. There is no intensive, they're forced. That's not the same thing.
It's a shame too because the level design and weapon design meant that if I were to switch between weapons freely, there would be a good amount of tactics to it. Plus most of the weapons are quite fun to use, although a bit similar in usefulness. I understand that wanting to incentivise players to use different weapons, but surely the whole reason for that is so they get the experience of assessing the situation and figuring out what works best, that's irrelevant when its randomized.
Couple of nitpicks.
The chargeshot not shooting all the distance when the reg shot does felt off.
The laser was confusing. Like "do you have a recharge or do you have to get close to an enemy?" kind of thing.
Spikes hitting you from the side is so annoying. This could be an art or gameplay fix, either convey they have side spikeiness or have them just not.
Overall, most things are done well but the core mechanic is the game's biggest flaw. I can think of some subtler solutions to getting players to try different weapons, but to flip the problem on it's head and ask "how would you get this mechanic to work better" is a lot tougher question. I've seen it work in more arena shooter style games and I think it works better there because you don't control the pacing, you can't just sit back at weapon switch. So perhaps if this were more of a run n gun like contra where the pressure's always on and the change was more clearly broadcast then it might work better, since in both the focus is on adaptability. This more Megaman like design suits....well Megaman, a game based more around decision making (which there is a lack of now).
Lastly, I know this is quite a critical review, so I just wanna add it is impressive given the time constraints, and given more time I'm sure some of these issues would be ironed out.