Hi Daniel,

Well begun! I think you have established the theme firmly, and this is what an exposition should do, so that the listener can better follow what you are doing later, during your development. Your movement of the the theme from E minor through a number of keys not only helps to impress the theme on the listener, it also adds drama, which is heightened nicely by the faster A minor section, with its diminished chords, as well as the chromatic movement in the F# minor section.

It will be interesting to hear the second theme, and the rest of the movement, as well as to see what kind of instrumentation you choose (assuming that you aren't planning a symphony for strings and percussion). That you imagine it might sound something like Tchaikovsky gives a bit of a hint, perhaps. Certainly Tchaikovsky was a master of playing an orchestra, and looking into how he achieves his sound is worth the time. There are a number of scores you could find using Composer's midi search function.

Technically, if you follow the standard issue sonata allegro form, you don't have to write the recapitulation--just change the keys. So with the second theme already composed, once you work out the development of the two themes, you have the first movement basically sketched out.

I'll be looking forward to see how not only this movement, but the entire work, progresses.

all best,
mgj