I was a child through the 80s-90s, and in Europe that means that I played video games on a system that doesn’t exist really any more. [For me, it was always Commodore - C128 to various Amigas - but others will remember the ZX Spectrum, the line of Atari computers that rivaled Commodore for and so on].
This was also the era of coverdisks being a thing - I got to play a lot of demos of commercial games (and full shareware and public domain games) via monthly computer magazines - and I’m sure that going by “most played”, some of those are going to be in this list…
…in fact, I am pretty sure that Scorched Tanks [Scorched Tanks - Wikipedia], was probably my most played multiplayer game of my teens. Sure, it’s “just” an Artillery game, but it had a huge array of loadouts and terrain modification effects (“liquid plastic” to make a surface rubbery to reflect shells, for example), and the game music is [in common with many Amiga games, especially compared to IBM PCs of the time] actually pretty good.
(Runners up are a bunch of the commercial fighting games of the period - Mortal Kombat, Body Blows, and so on - and a bunch of Thrust-style games - Gravity Force [and Amiga magazine Amiga Power-sponsored “sequel”, Gravity Power], R3 etc - as well as probably the better-known-Amiga-artillery game, Worms [better comedy than Scorched Tanks, less interesting effects])
in the commercial games space, though, almost certainly my most played and most thought about games - although I never finished either of them, were
Cannon Fodder - Sensible Software’s controversial-at-the-time anti-war tactical top-down small-team shoot-em-up. (For again, the music, the level design, and probably actually because everyone else was playing it - but it manages a lot of tension in most of the levels, just because you have usually less than 5 men [and in some missions maybe just 1], all of whom are just as fragile as the enemy… and the enemy are small blobs of pixels wearing camo fatigues suited to the terrain…) I remember that there was enough buzz about Cannon Fodder when I was at school that we’d spend a lot of time discussing tactics for difficult missions for several months after it came out.
Hired Guns : DMA Design’s full-3d 4-viewpoint SF RPG, notable for coming on a ridiculous number of floppy disks [8, I think?], and luckily having awesome music that played during loading screens so you didn’t mind spending some time swapping them. [And for, even more generously than usual for the time, coming with not just a manual, but two additional booklets - one with potted biographies of the player’s team and some in-game-viewpoint discussion of some of the technologies, and one with a short story set just before the game begins!] Hired Guns is brilliant, but also super hard (and clearly limited by the technologies of the time - the world is full 3d and real-time, but you’re constrained to moving on a grid and turning on one too), and I don’t think I ever got more then 30% into completing it!