This is an Oriental fruit-fly. You can see the halteres in pic #2. For those not in the know, halteres are the 2nd pair of wings (or what's left of them anyway). The diff btw bees and flies are bees have 2 pairs of wings while flies have one pair and the halteres. This particular fruitfly is considered a pest and their larvae are usually responsible for destroying fruits, and in the past have been known to cause huge losses to fruit farms all over. I guess agriculture is not a big thing in urban Singapore, so this fly is not considered a pest here.