It doesn't work like that, for films.
You remember Star Wars, right? You could make the argument that that was open-ended (after all, Darth Vader gets away with some henchmen pilots, the greater Empire itself still exists, allusions to pre-history and future have been made, the location of the Rebel base is still compromised, etc) BUT the actual adventure of the film itself has been neatly wrapped up and there is an "end".
Heck, even horror-film franchises wrap themselves up to give the viewer a sense of satisfaction and fulfillment (before the obligatory foreshadowing of the 11th sequel, right after the credits have finished rolling).
If you want to see a film that tries to "clifthanger ending (...) grab people's attention where they want to see more. The story has to build up to it." that fails, get a copy of
Carnies and watch it. Absolutely nothing gets resolved at the very end, and it's all one big pitch to lead into the sequel that will probably not be made any time soon/ever. (You should also buy it, so my buddy makes some bucks back on the money he sunk into it
)
You can't get away with blue-balling the audience, unless you've found that magic formula in the first film that
demands a sequel - similar to how Matrix, Back To Future, Pirates Carribean, etc all had their parts 2 & 3 rapidly written & greenlit to capitilise on an existing (and memory-fresh) winning combination.
I know that you are very passionate about your
I, Creator project, but I'm not seeing this as a winning business plan for your next film... and like it or not, film is a business. I still think you spent far too much money on your first cyborg film; I'm hoping that you can get the finer details figured out before spending so much on the sequel.
Trying not to ramble.