Since it's a curious question, let's take a step back from the obvious Christian answer to the question and think about it from an outside perspective.
I don't think it is possible that all religions lead to God. One might argue that different religions have different names for the same deity (we say Yahweh, he says Allah, she says Krishna etc) but when some religions believe in multiple deities it doesn't work as well to claim they are all different names for the same thing. Someone might argue that Yahweh and Krishna are one and the same but to claim that Vishnu and Ganesh are the same rather breaks apart the fundamentals of Hinduism.
The branches of Satanism that claim that Lucifer is the true God and Jesus is the imposter clearly differentiate between their god and ours. I don't see any way that anyone could claim that their faith leads to the same deity as the Christian faith.
Since atheism is arguably a religion (on the basis the belief that there are no gods is as much a statement of faith as the belief that there are one or more gods) it clearly does not lead to any god. Other faiths seek to end the cycle of reincarnation with the achivement of nirvana, and therefore don't seek a path towards a god as other faiths would understand it.
Even if we only look at religions that worship one or more deities it is hard to see how they can lead to the same place. Ignoring the technicality that they all lead to "god" in the sense that they all lead to the deity or deities worshipped by their adherents and assuming that the question is intended to ask whether they all lead to the same place, I don't think it makes any sense to claim that they do. The belief in some kind of afterlife featuring either rewards or punishments is a fairly common theme but what we must do to receive the reward and/or avoid the punishment varies widely, as does the belief in whether we get one shot at the prize or as many shots as it takes.
When each faith requires such different things of its adherents it is hard to see how they can possibly all lead to the same place. If Christianity is true then the only way to heaven is through Jesus Christ. If this is the case then Muslims are wrong. There is no other way. If Islam is true then the way to heaven is through living a life in accordance with the requirements of the Qu'ran. If this is the case then Christians are wrong. There is no other way.
It is arguably plausible to argue that we might get to eternal paradise by either accepting Jesus Christ, or by living a life in accordance with the requirements of the Qu'ran. But when Jesus said that nobody goes to the father except through him it starts to break that possibility. Therefore we have to accept that if multiple ways to God exist, Jesus was wrong in his assertion that he is the only way. If someone claims to be the only way to God and then turns out to not be the only way then we should wonder whether they are even a way to God, at which point we have to doubt whether Christianity is a path to God at all. That doesn't mean it isn't, only that the combination of observations would indicate it may not be.
We might argue that each faith has its own system of rewards and punishments that only apply to its adherents. In other words we might argue that those who profess to be Christians will be judged as described in the Bible, those who profess to be Muslims will be judged according to the Qu'ran and so on. That would create a curious situation in which there are multiple variations of paradise, multiple variations of punishments and also the potential for simply ceasing to be. Although this situation may appear to be at least theoretically possible it doesn't fit very well with the claims of major religions that they apply universally. One might argue that those claims of universal application are flawed but starting that path immediately invites speculation as to what else about the faiths can be summarily discarded. Although this approach does create the kind of situation that looks like Pascal's Wager on steroids, theoretically allowing people to identify with multiple faiths in the hope that they get at least close enough to the required standard in at least one of the faiths, that also falls apart when the requirements of one faith clash with those of another faith. We might try and pull technicalities offering prayers and praise to Vishnu and Ganesh while putting Yahweh first (thereby technically complying with "You shall have no gods before me") but, if this scenario were real, it could potentially just invite multiple deities to inflict punishments upon us if we notionally followed them but failed to adequately follow them.
Long story short, I struggle to see how the argument that all faiths lead to God holds any water, even when ignoring the claims of any particular faith.