This piece is one of my all-time underplayed favorites. I played this probably 7 years ago and I love it! Please don't take my comments in a negative way. I only mean to be constructive and honest:
The beginning needs to be faster, but don't make the notes uneven. More crescendo on ascending arpeggios and decrescendo on descending arpeggios. When Theme 1 comes in, voice the melody more and don't be quite so metronomic -- let the piece go where it naturally wants to go, right now it sounds like you're holding it back. The ornamental arpeggios on the second page need more flair and grace -- they're supposed to be improvisations by Mendelsohn. Generally the fast notes all need to be faster and lighter. In the middle section, those fast and loud notes need a light touch and a steady tempo -- this is not the lyrical part, this is the fury part. Generally speaking, the piece needs more life than you're allowing it to have. The measure before Theme 1 comes back in near the end, the RH should be quieter on the octaves and I'd like to hear you voice more of the B-G#-F# in the LH.
You do have a good tone to your playing, though, and seem to know the piece fairly well. Any chance you have learned the rest of the piece?
Topic: Fantasy in F# minor, Op.28--Mendelssohn