Please do not start with this game if you want to get into metroid! If you want to experience the first game in the timeline, play Zero Mission (the remake of this game), or if you want to start with a more linear experience start with Fusion. The only reason anyone should play this game today is if you are already a metroid fan and you really wanna see how the series started cause this game is not good. Plus if you play Zero Mission and you still feel the need to play this game, Zero Mission includes an emulation of the original metroid with its only unlock requirement being beating an actual good metroid game.

The lag and sprite flickering are annoying and slow down the pace of the game even more than its already slow gameplay. Being unable to shoot downward or crouch also make actually hitting enemies really obnoxious to the point where it's not worth trying to hit anything until you get either the screw attack or the wave beam. I haven't played the og metroid 2 yet, but I am pretty confidant that the simple addition of being about the crouch and shoot downward already make it much better than NEStroid.

The screw attack is by far the best upgrade in the game and greatly improves its playability but its also really janky. It feels like it doesn't work about 30% of the time which really adds up in a game that will require you to grind for health or missiles at some point if you are going for 100% like I did. The drop rates for health and missiles especially are also terrible. The missile drop rate is randomly decided when you entire a room and once you hit that random cap, no more missiles will drop until you enter a new room. This random number can be as low as 0, so if you're really unlucky with the rng you can spend as long as 30-40 minutes grinding for missiles and health.

Exploration is pretty bad as well. I didn't have trouble navigating without a map since I've played Zero Mission many times, but NEStroid has so many "hidden" paths that lead nowhere and there are many areas which would have greatly benefited from some sort of hidden shortcut to reduce the amount of backtracking or taking overly long routes to what should be an easy to reach destination or item. A bunch of the rooms have the exact same layout too which can get confusing if you're not keeping track of where you're going or if you're unfamiliar with the general metroid 1 map layout.

As far as positives go, most of the music still holds up really well. Brinstar and Kraid are obvious highlights, but tracks like Norfair and the escape sequence are also pretty solid. The only track I really don't like is Ridley since I think the loop is too short so it gets really annoying.

I cannot stress enough, do not play this unless you really need to know how the series started. That's the only reason why I finally got myself through it after multiple attempts over the years. It's a game a have a lot of respect for since it started one of my favorite videogames series, but I'm never playing it again since Zero Mission completely replaces this game.