I definitely enjoyed most of the time I spent on this classic Flash game; it's got a bit of that mid-2000's edge seen in many works from its' era and gives a cool twist to the tried-and-true Mario formula we're all used to. The level design (for the most part) is tough but fair, providing a solid challenge throughout the game's 16-level runtime; the art, albeit heavily referenced from the SNES Mario titles, has a nice charm to it and the music choices are pretty good too, if you don't mind the old-school Flash compression applied to all sounds. When it works, it really works.
With that being said though, there are a number of issues that plague this game, namely in how it controls and how the hit detection works; movement is slippery and inaccurate, and the hitboxes are really finnicky and don't always line up where you think a hit should or shouldn't count; these things are magnified during the game's last few levels which not only require immense precision, but have certain sections where you'd either get blindsided if you aren't quick enough or seemingly force you to take hits in order to get by.
Ultimately though, I have to cut this game a little bit of slack since it is approaching 18 years since release at the time of writing, but I wanted to give my honest thoughts and opinions on this Newgrounds classic. I'm definitely looking forward to my time with the sequel whenever I get around to playing it.
I rate 'A Koopa's Revenge' by Lambtaco...
3.5/5 stars!