Super cute artstyle and cool concept! I do wish you could hold the arrow keys to move as well. I got up to 14 packages delivered!

I'm impressed by the artwork. It was all made during the jam, right? It look quite cozy

The audio, unfortunately not much here. There is a music slider but I don't hear any and the one sfx is the single footstep sound. First up - it sounds really heavy. Not sure what that mailman is made of but if it's not steel then not sure how would he make that noise so first up probably pitching it up would help. And also since you have only one sound effect for the footsteps then it starts to sound monotone. There's a good trick for this. Every time you play the sound effect you can randomly change the pitch (somewhere between 0.9x and 1.1x pitch is a good start) and maybe even volume. This makes it seem like there are more sfx but with less work.

The controls seem quite odd. I had to squint my head a little to use those controls. WASD doesn't work well when everything is isometric. You could instead make it so the player goes in the direction of the mouse - that could not only make it more comfortable but more interesting.

Another thing is the UI is really far from action and at times I spend quite a few seconds before I realized I don't have enough letters. Instead of making the UI static in the bottom right corner you could have the number of letters above your head so when it reaches zero you already know that (maybe even adding an sfx for that would make the gameplay smoother). Also I have no idea why does the game always stop exactly after 46 seconds.

Don't worry about the length of the comment, that's just how I write :) I just wanted to throw out a bit of suggestions that could make the game a bit more accessible. Nice game

The artwork is very nice - well done guys! :D