Nice intro. This gives some Castle Crasher vibes, so it's got some retro Newgrounds vibes. Which comes with some pros and cons. The use of the strings and the composition as a whole might be a tad too simple, but it has a good blend of orchestral and electric instruments. I'm not the biggest fan of the mixing. The synth that joins in at 1:12 feels like it comes in a little hotter than the rest of the mix and it's a little harsh on the higher frequencies. There's also some unchecked reverb that makes the mix sound a bit too busy and crowded.
Other than that, I think the writing is decent. It doesn't wow, but there's some good use of melody, and there's nothing abrasive or grating. There's aspects of it that I like, for example the synth octaves at 2:10 has a nostalgic vibe for me that take me back to NES days.
Decent piece. What I really appreciate about this is the older Newgrounds vibes this has. It would be really interesting to see you explore that feel more.