I like the graphical style, and I like the mushrooms as a mechanic to jump higher. It forces you to think about when you're going to eat them and figure out what you can and can't accomplish without doing so, for fear of wasting mushrooms.

I beat the game on the first try, which probably doesn't come as much of a surprise due to the low difficulty and short length - however, I think that if you were to make a longer version the player would need a bit more guidance.

The main beef I have is the difficulty in understanding the environment. I kept having to wonder what was foreground and what was background; you could stand to improve the background sprites to give a greater impression of depth of field. I also think that at the beginning it's difficult to figure out what you're looking at - I definitely stood over the trees/shrubs for a while, trying various buttons, because I thought they were the mushrooms I was supposed to eat. Obviously once I found the mushrooms it became clear what they were, but I had to find them first.

The background itself could be improved too; the simple blue was a bit underwhelming. There is, of course, a risk of the background being too busy, but I think that could be mitigated with (again) a bit more emphasis on depth of field in the graphics and visuals. The start and end screens are also a little weird, since they don't look anything like the game stylistically - I think that if the text looked more like the in-game style it would look like a more complete package.

Everything handles pretty well, though, and the goal is made very clear, so you've definitely earned at least 2.5/5 in my book.

This game was fun, but it had a couple flaws that I think would make it a lot better.
It definitely needs a display so you can see how many keys and coin bags out of the max
you've collected, because even though I finished the game in one try, It was a little confusing
in the middle. On top of that, some music would be really good. It felt kind of empty for most
of it. Other than that, I like the idea and the sprites were good! Keep it up.

Quite good game, I liked it.
It would be nice to see an indicator of how many keys and coin bags you have (and need to collect) so you can plan better and don't run out of keys.
You can cheat a bit on the ground floor by going around the edge of the screen instead of unlocking the door to save a key, although there's a substantial risk of death if you miss a jump and fall. If this isn't intended, you could simply block us from going behind the edge of the screen.