The recent flash game Death vs Monstars, playable on several websites, is a hardcore shooter openly inspired by dual-stick shooters such as Smash TV and Geometry Wars. The reviews for the game have been strange: they have reservations about its derivative nature but recognize that it is fun. The IndieGames Weblog says it contains "such silly gimmicks as 'Berserk Mode' and 'Bullet Time'" but nevertheless it is "great fun." The Digital Battle reviewer writes: "It's a clever little game, make no mistake on that one. There's lots of enemies and tons of power-ups, so you'll likely have lots of fun playing with this casual shooting experience." This review strikes me as odd: one rarely associates "casual" with "tons of enemies and tons of power-ups." The overall tone of the review is positive, but this excerpt makes the game sound completely uninteresting: enemies and power-ups have been done to death (pun intended), and "casual" is often used to mean "easy." Jay is Games is more positive: "As brainless as Death Vs. Monstars comes across, it is constructed smartly. Monsters appear in well-paced waves, and their movement patterns complement each other." What I find lacking in these reviews is that they focus on the game mechanics while ignoring the dynamics. Here I am using the definitions of "mechanics" and "dynamics" put forth by Hunicke, LeBlanc and Zubek in their paper MDA: A Formal Approach to Game Design and Game Research: "Mechanics describes the particular components of the game, at the level of data representation and algorithms;" "Dynamics describes the run-time behavior of the mechanics acting on player inputs and each other's outputs over time." In other words, the game mechanics are what the player can do, which in the case of DvM includes moving, shooting, upgrading, and so on. The dynamics are what actually happens when the game is played. This critical review is an attempt to explain what makes Death vs Monstars compelling by examining the game's dynamics.

Arguably the most important aspect of the game is the control scheme. In DvM the player controls Death with the mouse while Death shoots an endless stream of bullets backwards. Holding the left mouse button locks the current firing direction, allowing the player to move in any direction while firing the same way. Double-clicking will cause Death to enter "berserk mode," which fires several rings of bullets and transforms enemy bullets into money. Holding the space bar enables "bullet time," which slows down all enemies and their bullets. Despite its simplicity, much of the game's depth comes from these controls.

At first glance the fact that Death always fires backwards seems like a hack, a poor attempt to duplicate the dual-analog control of Geometry Wars and Smash TV, where firing backwards is a common tactic. Using the left mouse button to fix direction or "strafe" also feels like a hack, giving the player marginally more control. However, this control scheme creates a surprisingly deep dynamic. Unlike dual-analog shooters, in DvM it is extremely difficult to change fire direction quickly. Frequently, the optimum strategy is to hold the mouse button, fixing the fire direction, in order to concentrate on the largest groups of enemies. On the downside this leaves a lot of space for enemies to attack. Gameplay-wise this results in fixing the firing direction for a few seconds, then re-positioning Death and the fire direction for a few more seconds. In essence, the player is constantly re-defining the space in the game, dividing it between attackable and un-attackable. For example, if the player situates Death in the lower-right corner while shooting towards the upper-left, Death's bullet stream covers a large space, making it attackable and quickly destroying any Monstars in that area. On the other hand, the space behind and around Death becomes un-attackable and hence dangerous, because it will take a few moments to re-position Death to attack Monstars that appear in that space. In any twitch shooter a few moments are an eternity, so the player must always be planning to change position and attack direction.

Another element that makes Death vs Monstars unique is the upgrade system. Although countless games use the same "kill things to get better at killing things" feedback loop, in DvM money encourages the player to constantly engage in risk-reward thinking. This happens because all of the enemies drop money when killed, and the player will naturally want that money. Because the control scheme causes the player to kill enemies in one area at a time, usually there are a lot of Monstars between Death and the money, making it extremely difficult to acquire. This is where "bullet time" comes in: by slowing down the action it is much easier to fly into dangerous space, grab the money, and re-orient the firing direction before the Monstars can react. Unlike other hardcore shooters, the enemies in DvM do not fire complex bullet patterns, and Death's hitbox is relatively large. Because of this, bullet time is rarely useful for actually dealing with bullets.

The upgrade system has another potential consequence, depending on how the player is choosing to play. The Jay is Games review notes that the shop is "abusable." This is because it is possible to replay older levels to farm money. Also, if a player dies midway through the level they keep any money they had collected. A dedicated player could theoretically replay the first level over and over until they can purchase every upgrade. However, the short length of the game enables a different sort of strategy: if the player decides to go through the game without repeating levels, the shop becomes extremely important. Unless they die frequently, the player will be unable to afford every upgrade so they must carefully consider what to purchase. There is a constant choice between upgrading now to make the next level easier, or trying to beat the next level as-is, so as to buy an even more powerful upgrade later. Upgrades also allow the player to tune the difficulty: not purchasing them can make the game significantly harder.

How frequently players actually chose sub-optimum weapons or similar equipment, in any game, is another matter. Intuitively this seems uncommon, as evidenced by the enormous market for powerful items from MMORPGs. Using these types of feedback loops to improve an avatar or other in-game object seems to be intrinsically pleasing: an enormous amount of tower defense games and RPGs depend almost entirely on the player's ability to maximize such loops. What makes DvM interesting is how the short length allows the player to experiment with the loop and rapidly understand it.

What I have tried to do with this review is show how games in general, and Death vs Monstars in particular, cannot be adequately described in terms of their mechanics. DvM is a great example because so many of the game's mechanics are seen elsewhere, which initially makes the game seem derivative, but by examining the dynamics we find that it is actually quite innovative. For example, explaining the control system says nothing of its fundamental impact on strategy, and mentioning the upgrade system does not reveal its many affordances. Similarly, descriptions such as "tons of enemies and tons of power-ups" or "berserk mode and bullet time" do not tell the reader how the game actually plays. This is why the reviews quoted at the start of this article were conflicted: by focusing on the mechanics they only saw what was derivative. They recognized that the game is fun, but not that the fun is in the dynamics. Reviews that focus on dynamics can provide a more accurate description of how a game plays, giving the player a better idea of whether they will enjoy the game.