I experienced no lag from the NG medal popup. So please do not remove that from future projects.
More Games link didn't work.
Game over without continues is an outdated game mechanic. It has nothing to do with retro. It's just bad game design.
Music and graphics were excellent but I would have liked to see variety in the color schemes and more sound tracks.
I got to level 8 and died. If there was more variety after that, it came a bit too late for me.