While it is cool and laudable that you made it for the NES, it does work against you in this case as most people do not have both an NES and a flash cart and are not willing to download an emulator just to play a ludum dare game (which I did do just because everyone deserves at least one vote for their hard work). It is a shame because the game is quite fun. I just have a few suggestions. The jumping and movement is a little janky and takes some time to get used to. Sound would also be nice, but considering that this was made for an NES, it's understandable that music and sound might be hard to make for it.

Infinitycore is right.
I'm probably one of the rare LD participants that has as NES emulator already installed, but I'm not sure if I would've downloaded one had I not.
Big review for you then.

Okay, the game.
Nintendohard! In a good way. Getting the timing for jumps right is crucial in this game.
Therefore sounds would've been nice to have, as Infinitycore has said as well. This is sort of the communication of the game with you, which brings me to the next point.
Some parts were unclear. I died after the first door aparently, I'm still not sure, because I didn't get the second key first in the second screen. There were more such things, but you get it.

I do love the level-layouts! Some parts were very well designed, like the long ladder were you had to drop off from into the high platform at the bottom. Good stuff!
Graphics were also good, some things make you think about another game though, so some more identity would help the game even better.

I encountered some bugs, but that's to be expected given the short time. Doubly so making a game for the NES and for that, I commend you!

Really impressed with the fact you made an NES game in 48 hours. The level layouts were terrific and felt impressively large the first run through. Loved it so much I am speedrunning it now.

Any% WR 2:25