As important as Dragon Quest 1 is, I didn't have a lot of fun playing it. Combat is turn-based, but there are no party members and you only ever fight one enemy at a time, so the strategy is minimal. There's not much story but it still has a lot of heart to it; the really basic setting is surprisingly compelling. The music is great and so are the enemy designs, and the key system is cool too. The game is also mercifully short which is good, otherwise I would've ended up too bored and quit.
If you're not someone who's really into experiencing old games for history's sake, you're not missing much by just playing a more refined later game in the series, or better yet, just playing Chrono Trigger. I think 8-bit action games aged much better than 8-bit RPGs, because while the former have an immediacy to their gameplay which still translates well in sheer fun factor, the latter simply couldn't reach much potential on this old hardware and needed more refinement to amount to much of an interesting experience. Granted, I played the Super Famicom version of Dragon Quest I, but it is still fundamentally an NES game in construction and feel. (And that is the version you want to play, if only for the more forgiving level scaling.)
If you're not someone who's really into experiencing old games for history's sake, you're not missing much by just playing a more refined later game in the series, or better yet, just playing Chrono Trigger. I think 8-bit action games aged much better than 8-bit RPGs, because while the former have an immediacy to their gameplay which still translates well in sheer fun factor, the latter simply couldn't reach much potential on this old hardware and needed more refinement to amount to much of an interesting experience. Granted, I played the Super Famicom version of Dragon Quest I, but it is still fundamentally an NES game in construction and feel. (And that is the version you want to play, if only for the more forgiving level scaling.)