blaster master ROCKS!
Blaster Master is one of those games that has nearly everything one could want in a video game --- great graphics (for the era, anyway...the backgrounds are nice and detailed, though there were still a few minor graphical glitches here and there, with water effects not yet made "realistic" until the day of the SNES), decent sound effects, a great soundtrack (with tunes that don't grate on your nerves after listening to them for a while, even considering how weak the NES' sound engine was compared to other systems that came after it), and a level of challenge that will test the skills and patience of newbies and veterans alike. Traversing each of the eight large, non-linear areas will probably pose the biggest challenge, as you'll have to sometimes exit the vehicle and search through doors to find power-ups and attachments for your vehicle (such as a wall-blasting cannon or hover jets) in order to proceed, all leading up to your fight against the mutant mastermind, known simply as the "Plutonium Boss".
You'd have to be pretty tough yourself to make it to the end of this game. With only three lives, no one-up items, no password or battery backup, and only a handful of continues, you'll be lucky to finish the game in a single day. It's all worth it in the end, though, as BM is one of those games that holds nothing back, daring you to play it again and again until you've finally conquered it.