This is so great! At first, I was a little confused and lost but quickly understood what was going on.

Dare I say it plays better than the original metroid (IMHO, Metroid only really becomes great with M2 on the original GB).

Gotta agree with Max on this, regarding the controls but I would also add that spotting the spikes and differentiating it from the "vegetation"(?) was a little hard. Perhaps adding some color-cycling to indicate it is damaging would help to convey this idea.

Pretty fun! Nice graphics and nice music

Critique: Thought the controls were hard to get used to and once upgraded, the jump was a little hard to control and it was hard to shoot with the right timing for enemies. 

I also ran into enemies that I couldn’t see because they were off screen

I’d love to see you keep working on this

Overall enjoyable. Really liked having the music and enemies not appear until getting the first upgrade. A few criticisms:

• The spikes and these decorative crystal(?) things have very similar shapes. This is generally fine since spikes tend to line floors and ceilings, however there is ONE rogue spike sitting on top of a platform that is very easy to overlook and get killed by.
• Enemies can sometimes hit you from almost a full tile away.
• It would be nice is items equip automatically and before the game is saved so that the player doesn't have to remember to equip their new item again after a death.

This was really awesome! The progression is solid for a game this short. It was fun to zip around the caves. The music and cinematic elements were great too.
I also would have wanted at least a "?" after "game over" at the end, but I had fun!

Great "clone".

Is interesting how you implemented some techniques using the tools that GB Studio offers you, I also love that engine, I would like us to exchange knowledge and impressions ;)

I feel like some things really don't work that well, like the collision with the doors.

Menu done with point and click style feels redundant and unnecessary, and even awkward.

That boisterous and unclear ending looks rushed and like you've unfairly lost.

There are some things to polish, but I see myself occasionally playing this game from my console once completed, please continue and finish it :)