If Guy Fawkes had been successful... Watch
In the long-term, little may have changed. I'd imagine James I/VI's successor would have continued with the colonial push, the wars with the Netherlands and Spain may have still occurred, etc.
A move to make Catholocism the main religion in the UK and all the negative impacts associated with that. A backward look on Science, an Empire that would've been a lot more brutal to it's subjects and a possible war between us and the Northern European Protestant states.
Catholicism does not have as backward an attitude to science as you think. The Reformation challenged Catholicism to be more open-minded though. I do think nations that are predominantly Catholic had more absolutist kings.
Certainly no English settlement of the American eastern seaboard, instead the Dutch get more room. They would probably not get on with the Catholic French, settlement probably still fairly localised. North America divided between French and Spanish interests and intermittent war on the plains for two centuries.
If the Protestants win the war in England then probable establishment of a Cromwell-type state in the 1610-20s. Catholic pogroms and emigration from England to Ireland and Catholic New France by the 1630s if this isn't too early to support them.
Personal union is off the cards as long as the Puritan state is around. If the monarchy is restored in mid-century it will not be Catholic. There's no wealth coming to England from America and the French and Spanish still have enough room over there for a few decades of peace so the buggers are going to try and invade us when we are at our weakest. The Puritans will fall one way or the other and we will probably have to go cap in hand to the Dutch and they might send over a William 50 years early.
If we somehow survive intact, a moderate William-type Protestant/parliamentary monarchy would arise and eventually unite with Scotland, and maybe even with the Dutch in a much stronger personal union if we're in a really bad way, but Scottish union would have to wait till a king could be found to do a personal union and then wait at least 50 years for full union - no Acts of Union before 1750 if we're very optimistic.
The Scots would probably have primacy within the union too.
The French would doubtless rule America and the world today, I think they'd probably beat the Spanish by the time they ran out of land and had to have a war. For England's and Protestantism's sake we would have to hope that was sooner rather than later.
I don't think the world would be as developed or democratic as it is today due to the decimation of Protestant power, it was no fun whatsoever but it was a more clear-thinking, revolutionary, science and technology-friendly ideology at the time.
The only way for Guy Fawkes to be successful and England/Britain to still become a world power is if by chance some Anglican royal survives and is chosen who can unite the English and the Scots under a personal union as quickly as possible and slash and burn the Catholics before France and Spain can react.
Not now, is agree with you. But historically it has. Just look at Europe. The more predominantly successful Northern European nations developed more quickly. ( incidentally, that's not having a dig at Catholics)
Not now, and not in history. Galileo Galilei was a believing Roman Catholic and most early scientists were clerics (such as Nicolaus Copernicus, an Augustinian canon at Frombork). Clashes with the Church hierarchy notwithstanding, the Church was by and large more a promotor of science than an enemy. The faster development of Northern Europe is, in my opinion, closely tied to Protestant attitudes towards proto-capitalism, more specifically money.
Sorru. That was more the area I was thinking about.