Really great game. 5 stars.
The Contra one is up up down down left right left right a
The real code has a B after the A but for some reason you dont have to put it in.
This game is extremely challenging. I played hard mode several times and haven't got past lvl 3. The easy mode isn't hard enough and the hard mode is too hard. It would be great if there was a inbetween difficulty.
On level 28 the button on the very right doesn't seem to work every single time, and that level took much longer than it should have. I really haven't encountered any other glitches. The game runs very smoothly and the puzzles were thought-provoking. I love the game, the added Easter Eggs were a great addition.