Making a game takes time; like, a lot of time. Making short games takes less time, which is a VERY valuable thing when you are only a few (or alone) working on a project. One can take a couple of years to make a big game, and in the end people may not like it and he would have lost these years. On the other hand, one can make a small game in a couple of months, which, if good enough, will reward you with popularity (for further games, or for your portfolio) and maybe even money. If it doesn't work, he doesn't lose more time and starts something completely different. If it really is a success, he can still improve it aiming at updating it or making a sequel.
 "My \"Dear\" Boss"){kind=icon}
 "Kingdom Rush"){kind=icon}
 "Ultimate Santa Battle"){kind=icon}
 "Pandemic 2"){kind=icon}
 "Armageddon"){kind=icon}
 "The Last Stand"){kind=icon}
 "Free Rider 2"){kind=icon}
 "Learn to Fly 2"){kind=icon}
 "Elephant Quest"){kind=icon}
 "Rebuild"){kind=icon}
 "Arcane"){kind=icon}
 "Isoball 2"){kind=icon}
 "Cover Orange 2"){kind=icon}
 "The Company of Myself"){kind=icon}
 "Elements"){kind=icon}