That description you gave sounds eerily like Warframe.
Seconded - it's amazingly well optimised and runs on pretty much anything. Don't be put off that it's a F2P game, Warframe (and Path of Exile) are absolutely on par with their paid counterparts, and much better in a lot of ways. Neither game makes you pay any money, and it's not in terms of 'you don't have to pay but...' - you honestly don't.
It doesn't have a very strong story, but it's got enough lore/etc to keep you pushing forward, and it has a ton of content now.
I get kind of annoyed every time someone says this about warframe. 90% of the game is grinding weapons, and warframes. Despite that, your inventory is
incredibly limited. For example, There are 35(?) warframes and ~50% of those have a prime version so 50-ish total. You have 3 slots to store warframes without paying money. Weapons are almost as bad.
Even more insidious, most prime items (frames and weapons) are limited time, so if you sell it you might
never be able to get it again. Also, some regular non-prime warframes come from quests and you can't repeat them, so if you sell them they are gone forever too.
Leveling up requires grinding weapons/frames, which requires grinding to get the materials for the weapon, so you might spend 5 - 10 hours grinding a single weapon (for materials + exp) then be forced to turn around and sell it for a token amount of credits because you can't level up anymore if your storage is full.
I don't even really care all that much about collecting one of everything, but I still eventually gave up in disgust because there was so much grinding to get something I'm just going to use for an hour and sell.
Someone will probably say you can earn premium currency ingame, which is true, but it's very much a "grind 500 hours for 3 cents per hour" type thing.
If you really, really don't care about that, then yeah the game is fine. The inventory is the only annoying part of the monitization.