I wasn't really expecting much, going off what others said and not being too keen on NES games in general, but to my surprise the game's pretty fun for what it is.

Unsurprisingly as the first game in the series, its fairly different from later games in the series. Lack of sliding, no charge shot, only 6 robot masters, and score count are among some of the differences it has. This might seem initially off-putting for anyone who's played the later games, but you can quickly get used to it at least. The difficulty is also fine, I didn't really find it to pose much of a challenge.

There's no notable story in-game, I assume its mostly in the manual.

My major complaint with the game would be that you require a specific weapon to progress at one point. The issue is that said weapon is treated as optional and you can easily miss out on it depending on the order you deal with bosses and whether you try a level again.

Overall, its a decent game. I wouldn't really recommend it to someone as their first Mega Man game, but give it a try if you've got some experience with Mega Man already.