Here are some of my hints and tips to improve and enhance your gameplay because I appreciate the game can be a little tricky at times and just damn unfair at others. You will need skill but lady lucky will have to be smiling for you too.
Each map has a specific objectives, and it's important to read those details. Turn-limits might dictate how quickly you need to push on, or perhaps the map only requires a single slayer to survive/escape meaning you can potentially afford to be more risky.
SPOILER WARNING! - If you like to learn how the AI works for yourself as you play then you might not want to read on. In this page I give away some of the behaviours of the vampire AI so that you can learn to control and herd the vampires as well as understand when it is safe and when it is not.
The key thing to providing cover and safe passage is to leave slayers 'behind' away from your progressing squad. Placing them in strategic positions can prevent vampires from getting into play thus covering your squad from behind. Sometimes it's even worth risking pushing a slayer forward just to thwart enemy reinforcements.
To do this get your slayer within 6 squares (you can cut corners and ignore doors when counting) of an entrance. Any mists waiting or appearing at an entrance where a slayer is within 6 squares cannot enter play. A slayer can cover more than one entrance if they are close enough to more.
Despite what they say about vampires in books, they are as scared of you as you are of them. This means they won't come into your view unless they have a chance of fighting you especially on Easy difficulty level. You can cover a long corridor by waiting with Line of Sight to where a vampire will have to turn a corner from a distance of 6 squares away. Any vampires waiting at a corner won't come at you. They will bide their time waiting from afar.
When playing Normal or Hard difficulty levels there is a slight chance the vampire will get brave and still run at you. In fact if the slayer isn't on alert they feel even less cowardly! At any difficulty level, vampires will try to rush the demolition slayer because they know that getting close might mean they get to keep their limbs! However if the demolition slayer is covered by any other slayer the vampires will back off.
These are more likely to get you killed sooner than actually help.
Can't figure out why things are happening, missed the tutorial levels? This should help a little bit.
Find out what it looks like. Viewer beware - these are developer graphics!