As of this writing, the show is cancelled. They tried shopping it around to other networks and online outlets like Netflix, but the show was super expensive so no one picked it up. When they filmed the finale, they didn't know that it was getting cancelled, so it was written as a season (not series) finale.
The final episodes introduce a new major faction from the future, and they heavily impact the status quo. The final episode has the main characters largely resolving the issues the other faction introduced. However, it doesn't completely resolve the story. Terra Nova is left in a moderately precarious state, and it's clear the other faction has plans that would have made them more of a threat in season 2. In terms of cliffhangeriness, I'd say it's maybe a 5 out of 10, there are plenty of unresolved plot lines, but no major cliffhanger that you'll wonder about.
Some details on what the second season would have contained can be found here.