Great game, I found all the secrets on my first run but still replayed it to see both endings to each level.
The music, artstyle and everything gives a nice retro-vibe.
My only real complain is the spikes usually being guaranteed to kill you most of the time.
Even if you have 3 health, since you don't get any invicibility-frames and the little jump you do usually isn't enough to actually move you out of the spikes.
Because of that, I'm pretty sure spikes were responsible for atleast 3/4 of my deaths.