You got the right idea in the intro and I love this idea (it reminds me of some atmospheres from certain SNES games), but the track needs more percussion/instrument dynamics to drive it as it gets slightly repetitive at certain points; however, the pluck at the end of the intro part sounded nice. The build up was pretty suspenseful even without a technical riser (proof that you don't need a generic snare build up :D ).
The drop is lacking a good sub-bass to back the sounds you created. Referring to Nightmare, you could hear the sub that backs it.. It would be a little different for a dubstep track because my sub bass was side-chained and constant throughout the drop (partially why complextro is a little easier than other bpm dubstep). Subs can be used effectively to emphasize certain sounds more or just to back the entire mix. You also want to ensure that something is happening in a drop at all times as well as making sure that you vary the sounds more. Each sound should bridge into the next one and therefore, flow. The drums don't have that much power in the mix in my opinion; however, that could just be me.
I think the bridge between the first and second drop could have had more. It should prepare the listener for the second drop by slowing down the intensity a little and slowly bringing it back up again. The bridge could have been introduced with a new melody first and then the part leading to the silence (and the eventual drop).
The second drop was kind of enjoyable. I suggest you keep practicing sound design and look into new ways to utilize Massive. Personally, I prefer Serum and find it much easier. I will eventually do more research on Massive too though. It doesn't matter what synth you use, but how you use it affects the quality and complexity of the song.
I have a lot of projects with random sound design that I scrapped because I believed it sounded either too generic or just ugly. Nightmare was the first track with 100% synth sound design and also the first track I finished without questioning whether it was good enough.
There is so much potential when you have a synth like Massive and I am sure you will come up with great things in the future with time!!!
If you have anymore questions, just let me know!