How to start a new game without going bankrupt

Based on 20 small games, 10 medium games, 15 large games, and 1 MMO:

1. Small games sell for 12 weeks
2. Medium games sell for 18 weeks
3. Large games sell for 20 weeks

MMOs behave differently. Instead of leaving the market after a set period, they have maintenance costs and income each week. You can add expansion packs to an MMO to boost income, or you can take it off the market to cut your losses.

Kalec's answer has some good general points but misses the actual question a bit, so here goes:

First, all features improve the game if they're included. Some are mutually exclusive, though - you can't have stereo and surround sound, for example. Obviously in a case like that surround sound would be a better boost to game quality than stereo.

BUT: Each feature costs development time to implement, and you only have a limited amount of it. If the amount of features you're pushing into a given field requires more dev time than you've allocated, the overall quality of that field decreases -- you'll see a percentile value behind the field name. When that happens, you'll have to pick and choose which features are really important, or allocate more time to that field.

Bigger games have more dev time, so can fit more features simultaneously.