Advertisements are a part of this application. Samsung and Asus users highly appreciate the app. Download the free .apk file of 100 Doors 1.5 and have a look at users' reviews on Droid Informer. This installer takes up 24 MB of disk space and it runs on Android devices 2.2 and higher.
According to the antivirus report, the app doesn't contain viruses or any kind of malware.
Users leave reviews saying that there are several drawbacks, they are an ugly UI, poor performance, annoying ads and multiple bugs.