This was a really fun little platforming challenge. Especially for a first game, this is great! I adore Gary, and the start and end cutscenes were great (as were the screen transitions)!
This was my best time after several attempts (in-game timer showed 40.something when I hit the door):
There's a lot to like here, and I was a fan of the level design. There are some QoL platforming things that I think could really push the feel of the jump (coyote time, input buffering, changing gravity at different points in the jump, maybe a little bit of accel/decel on the movement, etc.), but after a few runs I got a feel for how to make Gary go where I wanted him to. Even once I had his movement down, I felt like I had to play it careful instead of just letting it rip because there are some tight jumps in there.
I initially thought that the screen was too zoomed-in (in my first few runs I often got caught off-guard by spikes, and there were a couple of 'leap of faith' blind jumps), but I actually ended up kind of liking it; it kind of turned it into a memory game which I ended up liking; after a few runs I had a map of the level in my head and could better anticipate/avoid those things.
Two other little QoL things I would have liked would be resetting the timer on death (I ended up F5-ing the page when I died since I knew the run was lost, which took time that I could have been platforming) and changing it so that the end-screen timer matches what was showing in-game at the end of the run.
All-in-all, though, this was a really solid jam entry (and would be even if it wasn't your first game!). Definitely a fun time. Nice work, and hope to see more games from you in the future :D