Your god advocated the sacrifice of a man's son upon an alter, allowed the death of Able, committed genocide to clense the world, advocated slavery, domination of women, and a host of politically incorrect attrocities in the old testiment which were subsequently mollified in the new. This is the God of the Jews and the Muslems as well. The old tesitment is what the Jews, Christians and Muslims all share, it's the root of all the religions and thus the same God.
Islam may very well be a cult and false religion, for that matter so may christianity. But because they all have the old-testiment at their core (and islam has a form of the new testment incorporated since they see Jesus as another prophet) they, by all definition, worship the same exact god. Merely seen through different eyes.
Your god advocated the sacrifice of a man's son upon an alter,
In the case in point, the "sacrifice" of Isaac was a prophecy of the sacrifice of Christ, taking place on the very spot of the crucifixion 2000 years earlier. Abraham realized that he was acting out prophecy, which is why he named the place "The-Lord-Will-Provide," which in Moses' day spawned the saying, "In the Mount of the Lord it shall be provided" (Gen. 22:14). In any case, you'll notice that God didn't actually make Abraham go through with it, so your whole comparison is a non-starter to begin with.
. . . allowed the death of Able,
Yes, God allows us to do evil. He respects free will. That's not the same as ordering the death of Able.
. . . committed genocide to clense the world,
Yep. God respects free will, but there comes a point when He has to step in, take a hand personally, and pass judgment. He withholds His judgment as long as possible so that as many as possible can repent and be rescued.
. . . advocated slavery,
Debt slavery. It was the second millennium B.C.'s answer to bankruptcy. Those who so sold themselves went free on the seventh year.
. . . domination of women,
Actually, the Bible's rules on the subject are there for the protection of women. Even the ones that seem completely unfair make perfect sense when their cultural context is taken into account.
. . . and a host of politically incorrect attrocities in the old testiment which were subsequently mollified in the new.
Nothing was "mollified" in the NT, as if the OT were broken and needed to be fixed. All that the NT does is clarify the Old. Those who want to pretend that God suddenly got softer in the NT are deluding themselves, as are those who think that He doesn't show His love equally well in the OT.
This is the God of the Jews and the Muslems as well.
The God of the Jews, yes. We just have a standing disagreement on whether Jesus is the Messiah and whether the Messiah is God in the flesh, but we largely agree on God's nature and personality.
But Allah? He's the exact opposite of the God of the Bible. God delights in making covenants (relationships) with people and keeping them. Allah is presented as capricious in the Quran, untrustworthy. God cannot lie, Allah can. Allah calls his followers servants. God, on the other hand, calls His His own children, His brothers and sisters, His bride. Allah demands submission, God desires fellowship. For Allah, the only way to be certain of entering heaven is to die while killing Allah's enemies--that's why you have all the volunteers to be suicide bombers in the Islamic world. For God, the only way to get into heaven was through the death of His own Son.
The view that Allah and God are basically different names for the same Person is naive. Those of us who have studied both and don't have to worry about riots breaking out when we speak honestly can tell you that they're no more the same than Ronald Reagan and Bill Clinton.
Are you sure that Muslims recognize as holy the first five books of the Bible which contains the law given to Israel? That would be a real shock as the focus of Islam all over the world seems to be the destruction of Israel.