I had fun playing Alpha Prime, which I got on Steam for $1 during a sale. Metacritic score - 59.
Of course the game had by then been patched to decrease the difficulty, and I played it on Easy, so maybe that had something to do with it :)

Mount and blade got a 72 or something like that on metacritic and it's probably one of the lowest score games I have on my Steam catalog... and it's the one I've played the most WITHOUT any mods even.
Storyless, dated graphics, pretty much a combat simulator more than anything and it sunk many, many hours of my time. I can't say it was a "bad game" at all, but many players expect something else from it (like a plot and getting told what to do) and they get disappointed while others like it because of the mods mostly, but I thoroughly enjoyed the vanilla version until all the villages and cities were under my banner.
After I enjoyed it this much, I stopped taking reviews to heart and now base my decisions not just on reviews but also on player's opinions, demos and some other factors.

Its a shame they put out the demo they did for it, It nearly put me off getting the game. I wouldn't have until a friend took the plunge first and I got to play it on his computer. Great game as long as you understand that predators win in multiplayer.

Probably the most panned game that I've enjoyed is You Are Empty. Usually scoring about 2 out of 10 it got utterly panned. But I enjoyed it. The gameplay was pretty basic Painkiller style FPS. The character modelling was a bit rough. What voice acting there was sounded like it was recorded by students having a laugh.
But the architecture of the level designs utterly blew HL2's depiction of an Eastern European city out of the water, and more importantly the gameplay was strangely compelling. Simple, tried and tested, but effective. Probably a few too many health bottles though, but they could easily be broken in the heat of battle. All in all: £3 well spent.

Can't imagine how this was possible. It was my favourite game on C128 (I also really liked Iron Lord, Pirates!, Defender of the Crown and a few more I don't remember now*).
Countless hours I spent with this game, and yet I never finished it (although I was like 12 or something, when I played it for the last time).
*and also Last Ninjas, Maniac Mansion, Zak McKraken,
ps. I just found out there's a remake of The Detective Game! Yay!

I like bad horror movies, and I think that translates to liking bad horror video games.
Here are a few examples of survival horror games I love with their respective metacritic ratings. I just don't understand what is wrong with the critics
Kuon (PS2)- 57
Obscure: The Aftermath (PS2)- 60
LifeLine (PS2)- 61
Vigil: Blood Bitterness (PC)- 61
Obscure (PS2/PC)- 63
Disaster Report (PS2)- 66
Haunting Ground (PS2)- 67
Penumbra: Requiem (PC)- 67
Clock Tower 3 (PS2)- 69
Killer 7 (PS2)- 70
I also liked fast paced arcade action games that require a bit of skill. These don't always go over so well with critics. Here are a few examples of criminally underrated action games:
Crimson Tears (PS2)- 62
Gungrave (PS2)- 65
Gungrave: Overdose (PS2)- 68
Kya: Dark Lineage (PS2)- 69
Strider 2 (PS)- 69
Metal Slug 4&5 (PS2)- 71
Shinobi (PS2)- 71
The Red Star (PS2)- 72
God Hand (PS2)- 73
I find those last three particularly upsetting. They are three of the best action games on the PS2 and all 3 of them retain an old-school arcade feel. Some people think they got panned unfairly by critics for being too difficult.

I can't think of any games that I like that were totally hammered by reviewers, because truly terrible reviews are somewhat rare unless the game is fundamentally broken.
But, two that come to mind that weren't particularly well-received by critics are King's Field: The Ancient City (Metacritic 60) and Bloodrayne (Metacritic 65). King's Field is a niche series that reviewers never seem to "get," and Bloodrayne is simplistic, but wildly entertaining - one of my favorite turn-your-brain-off bloodbaths (I'd call it a guilty pleasure, except that I don't feel guilty in the slightest).
Thunderscape was largely ignored at release, and I think reviews of it were lukewarm at best, but I adore that game. I wish Ubisoft would stop sitting on it and let GOG have it.

I don't even remember how old i was, but no more than 10, i've felt the magic of the spell book called English-Polish dictionary heavily at the time.
A remake? Probably the DS one, i'll have to wait for a PC remake.;>

Beast Wars: Transformers. Doesn't even have a Metacritic rating, but GameSpot gave it a lousy 4.7. To be honest, it is not a great game, but if you were a fan of the old BW cartoon, it was definitely fun.

Equi-what?

Equilibris - a HoMM4 balance mod
Balances monster strength (so for example vampires are no longer OP), hero skills, adds some more artifacts IIRC, enhances map editor and something more.

That looks interesting. But i doubt it will work with my Czech version :-/
Thanks. some day i'll try it.

It works, I have a Czech version too. The only problem is that you will have some text in English (the added + changed text), the rest will be in Czech. I can live with it, however.

Clay Fighter for the SNES. Hell, even Clay Fighter 63 1/3 for the N64.
I loved Taffy and it has such quirky humor. :P