Whack some sense into the Sluperslugs to keep them away from the coolant tank!

Occasion:  Game Project 1

Engine:  Tengine

Project Time:  5 weeks 

Team:  2 Designers, 4 Artists, 1 Programmer

Contribution: Game Design (concept and enemies), 

 Level Design (battle map)


As the spiritual successor to Grail Guards this cooperative hero defense game puts you into the role of two engineers who have to keep a bunch of greedy slurperslugs from drinking the power core’s coolant liquid.


What I found most interesting is how Don’t drink the Coolant is a prime example of how focussing on a specific aspect can completely change the whole game and even though its hero defense core gameplay was based on the pre-existing formula from Grail Guards I would still say each of them can stand on its own as a game. Grail Guards as a base had many features that we could expand upon: there was the idea of giving the players different power-ups or maybe even different but complementary combat skills for each player to add more variety. Furthermore, one idea that we had discussed during the game jam but had to cut was introducing different enemies with individual behavior patterns. Last but not least, the map for Grail Guards was an empty plane with the grail in the middle - once again an aspect that we could change to give Don’t drink the Coolant its individual style.


The two players start their game in the middle of the map, each on their respective side of the walkway. Once the alarm sounds, the enemy sluperslugs will start to spawn from the four lanes to the left and right of the map and slither towards the coolant tank in the upper middle of the map. Each new enemy wave is announced by an alarm and will become more challenging than the previous one, so both players will have to help each other out by supporting their friend in combat and restoring the power core’s health with items.

Once the battery bar on top of the power core is fully charged, the players will be victorious. However, if the power core gets destroyed before that, the greedy sluperslugs will cause a city-wide power blackout which results in the players getting fired.



As a person who has been part of both development processes and tested both of the two games, it made me glad to observe that each one plays differently and is still able to stand on its own, even if they use the same core gameplay.

Due to its open map, and centralized point of defense Grail Guards has a much faster pace than Don’t drink the Coolant and can even be hectic at times. The fact that enemies can spawn from everywhere outside of the map and have an increasing number and spawning rate the player is more vulnerable and the difficulty curve slower but rising higher during the end when the player is literally bombarded with skeletons. Furthermore, the healing item has a stronger risk-reward element to it since the player can collect two of them but is unable to attack while holding the items, something we cut from the other game.

Don’t drink the Coolant had much more time for reiteration and balancing and it shows both in terms of difficulty curve (steadier and not as steep) and the cooperative aspect. Overall, I would say that this game demands more tactical planning because of the divided level map and the different enemy variants. And since there is a short buffer time between each wave the players have more time to communicate and arrange their tactic as well.