I saw this game being streamed and thought that it had an art style reminiscent of the era of freeware discs - something you'd randomly find online - like Jazz Jack Rabbit - and I mean that in the best way possible lol. The game was fun, I didn't get to the end, but I think I got fairly far. The difficult was just right, imo - which I think a lot of entries have trouble with difficulty settings and end up making things too difficult and I end up quitting in the first few minutes of game play (my personal philosophy is to try to make my jam game a little more on the easy side so that the player can get the whole gist of it - easier said than done of course).
I liked the twin stick shooter format, although found it a little jarring when the entire mech would be facing the way your point while moving in the opposite direction - I know it's a jam, so this aspect isn't that big of a deal, however, in my past projects that utilized a similar system, I would cut the sprite in half and flip the upper body when the player faces the opposite direction their moving.
Another thing I want to point out is the that the bullets would feel like they're moving slower when you're moving to the right while shooting to the right (comparatively to shooting to the left).. In my past exp, that was because the player would be moving while the bullets' speed rate is still at it's initial values - it feels weird how at times I'm almost running side by side or just a bit behind the bullet - I had to solve this by adding the player's speed to the bullet speed (or just giving the bullet a much much faster speed so it didn't matter what direction you're facing) when they're move and shooting in that particular direction.
One more thing, I think that you could have added health packs throughout the levels - or in Armored Core VI's fashion - adding a repair point. I would beat levels by the skin of my teeth lol - to which it would have been nice to have at least 1 health pack since the levels were kind of long
I really liked how many different weapons you were able to include and I'd say they all varied quite a bit and not just a slight rework of one or 2 weapons. They were fun to use. One bit of feedback though, is that I thought you too often grouped multiple weapons together - I figured to give the player more variety on what weapon they want to use, however, they were place kind of awkwardly. Once I got the weapon I wanted, I had to try to dodge the other weapon - which sometimes I failed at. A couple work arounds would be to place them in a way where they are more easily avoidable - or add a doom style arsenal where you can swap between weapons and pick up ammo for them to be able to use them again.
anyways, it was fun!