This is awesome!!! You basically made two games in one week, so great job with that :D
I think the pixel art style serves your game well, and you implement it perfectly. The audio is fantastic. Great SFX, love the music switch to chaosworld.
If you were planning on taking this game further than the jam, my critiques would be:
1) the platformer section isn't very fun. I'd spend some time thinking about what makes popular platformers fun and do some of that! Movement options, etc.
2) The camera is working against the player in both your games. I think this can be done intentionally to make a game difficult, but I found it a bad-frustrating. For the shooter section, I'd explore mouse-focused camera options if I were you!
3) The shooter section was too easy (at least up to the point I played) -- I could basically walk into/through enemies whenever and never got punished for it. Your platformer section, on the other hand, was frustratingly difficult. I think hard platformers can only be fun if they have a variety of movement options. I walked into the side of a torch returning from that second key one too many times lol.
4) I had a crash once when switching from platformer to shooter. Can't really give you more info than that sadly :(
Thanks so much for the play and the game! This is a really high quality jam :)