Deus Ex: Mankind Divided

I was really enjoying this game. Honestly I was. A sci-fi RPG set in a dark future, with cyborgs, adventure and guns. What's not to love right? I was having an 8/10 or higher level of fun while playing it. But then I hit about 20% og the way into the game, and realized I had been robbed. I got this game years after release, and was able to pick it up in a supermarket for the low price of £10, and I still feel totally, UTTERLY ripped off. I got to about 20% of the way into the game, to discover the credits rolling. "no" I thought to myself "there's... there's no way that's the end right? already? I mean... I only just started it? right?" I was utterly appealed at how short this game was. It's not a full release, its like an extended demo, its like A short spin-off game. I loved the world of Deus Ex, but if this is the length the games are, I'll not bother to play another again. It couldn't have been more that 8-10 hours of play, surely? For the amount of actual content, I would say this should be priced at like £4.99 brand new or something, as a short game to download on PSN. I feel stolen from that I paid so much for such a short game. I expected this to the be the end of the first act of five, not the end of the whole game. Outrageously short.