To make your arrangement into a MIDI file, if you use Finale Notepad, go to File - Save As... - (At the bottom of the box you will see the name of your arrangement ''Spin-Dig Galaxy[1]'' and then under it you change the Format or Type of file from ''Finale Notepad File'' to ''MIDI file'' by clicking the arrow on the right then you save and your arrangement should be in a MIDI format.HEY HEY! WASSSAP! My name is Arekushisu11, nice to meet you!
You seem to have quite an experience with music sheet composition because from what I can see and hear (Even if I'm still a beginner at compositing myself) from your first arrangement, you have quite a good musical ear and an ability to figure out the right timing, chords and other musical partition related aspects thingy. (Sorry, I compose arrangements for fun and only stick to the guidelines of the website to make my partitions as correct as possible. I don't know much about the musical language and only the basics about Finale Notepad.)
The only thing that you could arrange more, you do it if you want, would be the beat of the music. HOLY GEES, WHAT?! No, the left hand is correct, maybe it's to low... or is it... I dunno. Just a feeling. You should ask Dahans. He's better than me to point out these things. He has more experience. Anyways... I just listened to the original and compared it to your arrangement and felt like yours lacks a light beat the original haves. Not a big deal, just a little something that would make yours more lively.
Here's a link to the original so people can compare it with yours.
http://www.youtube.com/watch?v=vdwWE5tGaXcAlso, again just a feeling and no big deal, the right hand is a little bit more alive in the original and I think it has a higher pitch but, that's just me. I mean.. it's the feeling I got. Nothing more.
There might be other things to point out but, that's all I can notice about your arrangement at the best of my knowledge for now.
So overall, looks and sounds good. Just add a bit more ''life'' (Yeah... I know it doesn't tell you much about what to change but, if your musical ear is as good as I think it is, you should figure it out by yourself) to your arrangement and it should turn out great!
If you have further questions about how to improve or modified or whatever, even if you wanna know what time it is or did the chicken came before the octopus mutant, feel free to ask. I'll be happy to answer to the best I can.
Have an awesome day, morning or night whenever you'll read this comment!
See ya! Arekushisu11