You'll find the controls to be pretty straight-forward for this kind of game; use [A] and [D] to move left and right, respectively. Unfortunately there's no jumping, although that's part of the strategy, as you'll see soon enough. Use the mouse cursor to aim your bow, click and hold to draw, and release to fire. Longer draws will yield higher velocity, inflicting around 50 percent more damage than the shortest possible draw. As mentioned, the arrow mechanics (trajectory, velocity) are pretty satisfying compared to many other games of this kind; you're usually able to hit your target with pinpoint accuracy all the way across the battlefield, instead of just taking an "educated guess" as to where your arrow will strike. The only other controls you'll have to worry about are spell keys  through  (if you don't like clicking the icons), and using [Space] to extract magic from Rune Stones when you come across them.
Each level is a platformer-style terrain of slopes and hills that you'll traverse from left to right (and vice-versa, as levels progress). Monsters will spill out of portals and march towards you; some of them fire arrows like you, while the rest are melee fighters that need to be right up in your grill to inflict damage. The monster portals can be destroyed; in fact, they have to be to complete each level. After the final portal and remaining monsters are mopped up, you'll move on to the next stage. In later stages, you'll find yourself having to go back-and-forth instead of just left-to-right, as the number of portals in each level increases (they'll start to respawn). Along the way, you'll see the occasional Rune Stones that you can extract magic from in order to build your spells. You'll be exposed and unable to attack or move for a few seconds, but it's important to harvest every one you come across if you want to have a large selection of spells to choose from.
These spells can be created between each level by combining various types of magic together. There's a handy "recipe" book that lists the required combination for most of your spells, although you won't know exactly what each one does until you learn it. You can usually infer which are offensive and defensive by their names, such as "Rock Wall" or "Fire Storm." Some spells' purpose is two-fold though, keeping enemies at bay while damaging them at the same time. Before the level begins, you can swap out different spells and order them however you want. You'll also come across the occasional "Trinket," which is an item dropped from monsters (at a 1 percent drop rate) that augments your abilities with things like increased damage or mana regeneration.
Analysis: Sometimes it's easier to notice a game's faults when it actually happens to be fun and relativity well-made. You find yourself wishing for more, or disappointed in specific aspects that hinder your personal playstyle. If you're enjoying Sin Mark, it's not too hard to notice what's lacking, like a melee weapon for your character, more items/armor that boost your stats, or the fact that stats aren't even a part of the game. A character leveling system would have been great, with the ability to increase things like movement speed, hit points, attack power and more. Many people feel there should have been the ability to jump, even though most of the game's strategy is centered around the "push-or-retreat" of taking of ground (which would be rendered null if you could just jump over an enemy).
Despite this, Sin Mark still proves to be a valiant effort that's enjoyable, engaging and somewhat difficult to master. There's a lot of multitasking required; aiming your bow, gauging the right velocity, choosing the best spell for the situation and trying to gain ground while keeping enemies from doing the same. It's something that both action and strategy fans will probably enjoy, tiding us over until Bowmaster 2 is finally (and hopefully) released this year.