I avoid games rated below 7.5 so i'm not really sure but since your second post encouraged me, I will say infectonator. I don't know why it has such a high score, its pretty terrible in all fields.
Honestly gemcraft. I hate that game no idea why its so popular. Cursed treasure also is lame. After a few levels it is just repetitive without enough towers.
I found the non timed infectonator to be kind of fun... the most overated game in my opinion is crush the castle 2 games... how on earth does something like that get a 9.5? It deserves a 7 at best... worst game in general though... not really sure because I usually hear its good before I play it or it atleast has a decent rating or whatever..