The mountains are rather odd. The "spine down the middle" structure makes sense for islands, but not continents. Continents have mountains along boundaries, either coastlines (Like the Andes), or boundaries between "lumps" (like the Himalayas between Eurasia and India)

Using the projection indicated by the graticule over that extent would lead to significant and very noticeable distortion (everything at the top of your map would be stretched out east-west by a factor of 2), which your features don't show, and that means that the features themselves are distorted the opposite way (pinched in east-west) to compensate. No real life cartographer would use this projection for this map. They would probably use a Transverse Cylindrical projection (Most likely Transverse Mercator), or maybe something more exotic like a Two Point Equidistant (Often used for Asia), or Chamberlain Trimetric (Often used for Africa). As it doesn't extend too far south of the equator, a conic projection like Lambert Conformal Conic could also be used although I think that would be pushing it. Unless you've committed to things being where that graticule says they are, say be working this into a larger global map, you could most easily solve this by just changing the graticule and leaving the features alone.

"Meridian" is a term for any great circle through the poles, not just the one we choose to use as the basis for a coordinate system. That basis one is the "Prime Meridian" and in modern cartography we largely agree to use the meridian through Greenwich Observatory. You seem to have dropped yours in the middle of the map and it doesn't seem to run through any major cities. The only really practical concerns are established usage and the discontinuity on the far side which means it's desirable to have it avoid populated land. Otherwise it tends to amount to running it through something important like a capital or religious site. If you haven't already, you might want to think about where it should be and why. Picking this to fit your particular map extent can lead to it looking artificial. It's also not that common to highlight the prime meridian the way we highlight the equator, and even the equator tends not to be emphasized so much on maps with restricted extents compared to global maps.