Gmae mechanic approach Thread

I am searching for the best approach in gameplay. I know what I chose to approach in level design will finally effect level design and that is what I actually wanted to do. I want to ask some opinion from the creative mind in this forum. My question is which is better for gameplay for my third-person RPG game:

1. block the player progress by difference in player level and monster level. Player cannot progress because the monster is too high level for player so they need to level up first before they can clear the area. The level design for this approach will be more simple without any other thing that can block player from going anywhere except for the monster.

2. block the player using key and lock mechanic. Player need to find something or solve certain puzzle to unlock another area and continue with their journey. The environment design will be more complex since we need to structure the player path and puzzle for player to solve and it also increase the linearlity of the design.

So which in your opinion is the best design approach more memorable to implement to my game.

Ops... typo with the title and now i can't change it

Do both, so it doesn't get boring with every obstacle being the same.

If i do both which should I prioritized more, which is more memorable, fighting monster or solving puzzle?

There is no clear answer to that, because both options can be implemented poorly.
There's some tips I can give you though.
Do not alternate between both like "1,2,1,2,1,2,...". This is really predictable and comes off as cheap. The key and lock mechanic is THE cheapest way to block the player with puzzles. There's even games where you cannot open door X because you need tool Y despite having other, perfectly viable tools already. (Cannot open door with ax/crowbar/explosives-> must find sledgehammer). There's a line between pacing and unnecessarily padding a game out, that you shouldn't cross.
I recommend you to read this article: The Magic of Old Adventure Games - Extra Punctuation
Although you aren't making an adventure game, it should be a good read for you and you should be able to apply those concepts to pretty much any genre.

My final advise: Be creative! Don't restrict yourself to either option since there's tons of ways to manage progression in games.