It's not a bad movie, it's just far and away not as good as it might have been. You've got to blame the (sigh) writer/director for that although he did have a hand with the writing which is possibly why it's not as bad as it might have been.
First of all it's so derivative - the Jurassic Park series, of course, Running Man, Ender's Game, the Death Race series, and all the YA movies like Maze Runner and the Hunger Games. And loads more.
And, yes, it was made on a budget, hence the complain about the poor SFX although for a B movie they're not too bad. I was thinking they must have got a job lot of dinosaur graphics.
Anyway, taking all that into account, the story line isn't too bad as far as these things go - I can't believe one reviewer actually said it was original!! - go figure - and it's generally pacy enough to keep you watching, at least with one eye, although you know how it's going to end.
Maybe you've got to be in the right mood to watch something like this but it you are, give it a whirl.