Until a Moviestock reaches delist you are betting with or against your fellow HSX traders. It is only when a stock reaches delist (based purely on box office) that the stock acquires its 'true' value.
Most traders will buy or short a stock based on what they think the stock will ultimately earn in box office revenue, usually based on comparisons with similar titles (eg the last X-Men movie delisted at $250 so the new X-Men movie will also delist at $250). The more sophisticated the trader, the more factors they will weigh up in coming to their decision on what the film will gross.
The more factors you throw into the mix, and what weighting you give them, the better. Film is a business, but thankfully HSX doesn't look at underlying profitability of films so external factors are all that is required. The most powerful influencer on performance is who is releasing it - if a title looks like it will underperform versus studio forecast, will that studio spend obscene amounts of cash marketing the film to drive admissions regardless of the financial sense this makes? Does this particular studio's marketing department have a history is mishandling the genre of film you are thinking of investing in?
You also have to consider whether a particular film will be popular amongst HSX's userbase. I would guess that studio funded comic book films are likely to be over invested in due to personal taste rather than realistic box office expectations, so buy long on the IPO and then switch to a short position when more details are available.
All IMHO of course.