Now it works!
Sounds like you're well on your way already, as you said it's just finding the right sounds and working the arrangement so it's not too repetativep.
A couple of tips regarding the arrangement.
Instrument breaks
A great way to break the monotony is having something like a drum break which gives the ears a short break and then you can go back in to the main melodies and it sounds exciting again. It's like a chorus in a song, everyone wants to sing along to it but if it was only a chorus it would suck. The piano break at 2:10 in the original is a good example of this, it breaks the monotony but you know a thumping beat is just round the corner.
Arrangement.
A lot of VGM loop go in a very liner fashion very much an ABCD progression. Doing something like an ABCADC progression puts the A section in different context each time and gives it a lot life.
Hope this helps.