Yes, Islam believes there is no other God but Allah. As for Satan, he is an disobedient angel and is not a God.
Your expression "AS Allah accepts animal and human sacrifice he proves himself to be a demon god."
is questionable in nature. The Jewish God, which is the same as the Christian and Islam God.
When Mary offered up animal sacrifices is virtually the same as when the Jews used to offer animal sacrifices.
The expression "Muslims have lived in miserable condition and have shed blood for millions of years because of Allah."
is a compound sentence in which the first part is not true. Just look at Qatar, Saudi Arabia, Brunei , etc.
I do not think anybody would claim those people live in miserable conditions.
As for the later part of the compound sentence, that could be said also of Jewish and Christian countries.