If you own a gbc or gba then this game is a must own!
The 1985 is the standard 32 level NES game that came with duck hunt. It's a true classic and it's nice to have it in your pocket.
Challenge
This is the 1985 levels with hidden items in them like yoshi eggs and red coins. This is a more competitive mode and it's more for high scores and stuff like that.
Original 1987
These are levels strait from Japan and they are insanely hard. It is nice to have an extra 32 levels to play through, although it's pretty hard to make it to the end. I did beat this mode but it was extremely difficult and frustrating. I spent months being stuck on the same level.
Boo Racing Mode
This mode is very weird, but undeniably fun. You race through a level against boo switching panels so that you can make your way through the level more easily. It's fun, but it gets boring too quick.
Extras
All I can say is Super Mario Deluxe is packed to the brim with extras. There are high scores, photo albums, it has a yoshi egg finder, and is even compatible with gb printer.
Conclusion
In the end Super Mario Deluxe for the game boy color is an awesome game with loads of content. It is a bit too hard at times, but that's easily forgivable considering all the game has to offer. This game is a must own.