Higashi no Eden, Btooom! Recommendations
In both shows, the characters are chosen to be thrust into a survival game. All of the players are given items (bombs in Btooom and a concierge with the power to give you almost anything you want in Higashi no Eden) to either kill others or avoid being killed.
They are both in some kind of a "surivival game" where they have to do something to survive.
Higashe no Eden: they spend their money, to "improve" the country. And they will be murdered if the balance on their phones drops to 0$
Btooom!: they kill eachother with bombs.
Both have this romantical theme going, even though it's not that similar.
And both maincharacters use intelligence and agility to outsmart their targets.